Analysis modules

Formula node

Available since phyphox file format 1.7 (phyphox 1.1.0)

For simple calculations, you can either use the math nodes listed below or write it all in a single formula node. In most cases, when you would need multiple math nodes otherwise, the formula node is faster as it does not need to read and write large buffers multiple times but can do the whole calculation in a single step. However, in some cases, not all options are available in the formula node and the implementation of both versions are not necessarily identical.

<formula formula="[1]+sqrt((7+[2_])^[3_])">
    <input>singleValue</input>
    <input>multipleValues</input>
    <input>multipleValues2</input>
    <output>result</output>
</formula>

The example above takes a single value from the buffer "singleValue" and multiple values from the buffers "multipleValues" and "multipleValues2". These buffers are represented in the formula according to their order as 1, 2 and 3. If only a single value from a buffer is used, it is referred to as [1], but if multiple values should be used and the calculation should be repeated for each value and output a result for each value, an underscore is added as in [2_] or [3_]. The example then output the result of "A + sqrt((7+B)^C)", with A being the last single value from "singleValue" and B and C being the first value from "multipleValues" and "multipleValues2" respectively. This is repeated with the same single value for A but the second values from "multipleValues" and "multipleValues2" for B and C. In this example, sqrt is a common function across many programming languages and denotes the square root of its parameter.

The formula parser respects brackets ("(" and ")"), understands simple binary operants (+, -, *, /, % (modulo), ^ (power)) and common functions (sqrt, sin, cos, tan, asin, acos, atan, atan2, sinh, cosh, tanh, exp, log, abs, sign, round, ceil, floor).

Basic math

abs (absolute)

Calculates the absolute value of a single input element-wise and writes it to a single output buffer. This module will write as many values as there are values in the input buffer.

value

input

as not required

Number of inputs: Exactly one

abs

output

as not required

add

Calculates the sum of all inputs element-wise and writes it to a single output buffer. This module will write as many values as there are values in the biggest input buffer. If a buffer is shorter than the others (especially if one input is a single value), its last value will be repeated.

summand

input

as not required

Number of inputs: At least one

sum

output

as not required

divide

Calculates the quotient of multiple divisors from a single dividend element-wise and writes it to a single output buffer. This module will write as many values as there are values in the biggest input buffer. If a buffer is shorter than the others (especially if one input is a single value), its last value will be repeated.

For this simple function you can leave out the as attribute. If you do so, the first input will be used as dividend and all subsequent values as divisors.

dividend

input

as not required, but order matters if left out

Number of inputs: Exactly one

divisor

input

as not required, but order matters if left out

Number of inputs: Arbitrary

quotient

output

as not required

gcd (greatest common divisor)

Calculates the greatest common divisor of two inputs element-wise and writes it to a single output buffer. This module will write as many values as there are values in the biggest input buffer. If a buffer is shorter than the others (especially if one input is a single value), its last value will be repeated.

value

input

as not required

Number of inputs: Exactly two

gcd

output

as not required

lcm (least common multiple)

Calculates the least common multiple of two inputs element-wise and writes it to a single output buffer. This module will write as many values as there are values in the biggest input buffer. If a buffer is shorter than the others (especially if one input is a single value), its last value will be repeated.

value

input

as not required

Number of inputs: Exactly two

lcm

output

as not required

log

Available since phyphox file format 1.5 (phyphox 1.0.7)

Calculates the natural logarithm of a single input element-wise and writes it to a single output buffer. This module will write as many values as there are values in the input buffer.

value

input

as not required

Number of inputs: Exactly one

log

output

as not required

multiply

Calculates the product of all inputs element-wise and writes it to a single output buffer. This module will write as many values as there are values in the biggest input buffer. If a buffer is shorter than the others (especially if one input is a single value), its last value will be repeated.

factor

input

as not required

Number of inputs: At least one

product

output

as not required

power

Calculates the power of a base and an exponent element-wise and writes it to a single output buffer. This module will write as many values as there are values in the biggest input buffer. If a buffer is shorter than the others (especially if one input is a single value), its last value will be repeated.

base

input

as required

Number of inputs: Exactly one

exponent

input

as required

Number of inputs: Exactly one

power

output

as not required

round

Available since phyphox file format 1.5 (phyphox 1.0.7)

Round the values from the single input element-wise and writes the results to a single output buffer. This module will write as many values as there are values in the input buffer. By default it will round to the nearest integer. The attributes ceil and floor can change that to the nearest larger integer or the nearest smaller integer.

floor

attribute

optional, default: false

ceil

attribute

optional, default: false

value

input

as not required

Number of inputs: Exactly one

round

output

as not required

subtract

Calculates the difference of multiple subtrahends from a single minuend element-wise and writes it to a single output buffer. This module will write as many values as there are values in the biggest input buffer. If a buffer is shorter than the others (especially if one input is a single value), its last value will be repeated.

For this simple function you can leave out the as attribute. If you do so, the first input will be used as minuend and all subsequent values as subtrahends.

minuend

input

as not required, but order matters if left out

Number of inputs: Exactly one

subtrahend

input

as not required, but order matters if left out

Number of inputs: Arbitrary

difference

output

as not required

Trigonometric functions

acos

Calculates the inverse cosine of a single input (in radians) element-wise and writes it to a single output buffer. This module will write as many values as there are values in the input buffer. The module will calculate in radians unless degrees are specified using the deg attribute.

deg

attribute, Available since phyphox file format 1.2 (phyphox 1.0.3)

optional, default: false

value

input

as not required

Number of inputs: Exactly one

acos

output

as not required

asin

Calculates the inverse sine of a single input (in radians) element-wise and writes it to a single output buffer. This module will write as many values as there are values in the input buffer. The module will calculate in radians unless degrees are specified using the deg attribute.

deg

attribute, Available since phyphox file format 1.2 (phyphox 1.0.3)

optional, default: false

value

input

as not required

Number of inputs: Exactly one

asin

output

as not required

atan

Calculates the inverse tangens of a single input (in radians) element-wise and writes it to a single output buffer. This module will write as many values as there are values in the input buffer. The module will calculate in radians unless degrees are specified using the deg attribute.

deg

attribute, Available since phyphox file format 1.2 (phyphox 1.0.3)

optional, default: false

value

input

as not required

Number of inputs: Exactly one

atan

output

as not required

atan2

Calculates the two-argument variant of the inverse tangens (corresponding to atan(y/x)) element-wise and writes it to a single output buffer. This module will write as many values as there are values in the input buffer. The module will calculate in radians unless degrees are specified using the deg attribute.

deg

attribute, Available since phyphox file format 1.2 (phyphox 1.0.3)

optional, default: false

y

input

as not required

Number of inputs: Exactly one

x

input

as not required

Number of inputs: Exactly one

atan2

output

as not required

cos

Calculates the cosine of a single input (in radians) element-wise and writes it to a single output buffer. This module will write as many values as there are values in the input buffer. The module will calculate in radians unless degrees are specified using the deg attribute.

deg

attribute, Available since phyphox file format 1.2 (phyphox 1.0.3)

optional, default: false

value

input

as not required

Number of inputs: Exactly one

cos

output

as not required

cosh

Calculates the hyperbolic cosine of a single input (in radians) element-wise and writes it to a single output buffer. This module will write as many values as there are values in the input buffer.

value

input

as not required

Number of inputs: Exactly one

cosh

output

as not required

sin

Calculates the sine of a single input (in radians) element-wise and writes it to a single output buffer. This module will write as many values as there are values in the input buffer. The module will calculate in radians unless degrees are specified using the deg attribute.

deg

attribute, Available since phyphox file format 1.2 (phyphox 1.0.3)

optional, default: false

value

input

as not required

Number of inputs: Exactly one

sin

output

as not required

sinh

Calculates the hyperbolic sine of a single input (in radians) element-wise and writes it to a single output buffer. This module will write as many values as there are values in the input buffer.

value

input

as not required

Number of inputs: Exactly one

sinh

output

as not required

tan

Calculates the tangens of a single input (in radians) element-wise and writes it to a single output buffer. This module will write as many values as there are values in the input buffer. The module will calculate in radians unless degrees are specified using the deg attribute.

deg

attribute, Available since phyphox file format 1.2 (phyphox 1.0.3)

optional, default: false

value

input

as not required

Number of inputs: Exactly one

tan

output

as not required

tanh

Calculates the hyperbolic tangens of a single input (in radians) element-wise and writes it to a single output buffer. This module will write as many values as there are values in the input buffer.

value

input

as not required

Number of inputs: Exactly one

tanh

output

as not required

Statistics

average

Available since phyphox file format 1.2 (phyphox 1.0.3)

This module calculates the average of all values in the input buffer. Optionally (i.e. if the output is connected), the standard deviation is calculated as well (Corrected sample standard deviation).

buffer

input

as not required

Number of inputs: Exactly one

average

output

as required

stddev

output

as required

binning

Available since phyphox file format 1.2 (phyphox 1.0.3)

The binning module distributes the values from its input in into ranges (bins) and outputs a mapping of these ranges and the number of values in each of them. The bins are set to x0..x0+dx..x0+2dx..x0+3dx etc. Therefore x0 defines an offset of the bins and dx the size of each bin. x0 defaults to zero and dx to 1, so without these, the module defaults to binning to integer intervals.

The output can directly be used to display a histogram. binStarts will receive the starting values of each range (bin) while the count is written to binCounts.

in

input

as not required

Number of inputs: Exactly one

x0

input

as required

Number of inputs: One or none

dx

input

as required

Number of inputs: One or none

binStarts

output

as not required

binCounts

output

as not required

Advanced math

autocorrelation

This module will calculate the autocorrelation. It takes at least one input buffer y, but can take a second input x as well. If x is omitted, it will be filled with indices. Additionally, single value inputs minX and maxX can be set as well. These limit the x range over which the autocorrelation is calculated to improve performance. The module will return as many values as provided by the input buffer and fill the output buffer y with the normalized autocorrelation of the y input buffer. The x output buffer will be filled with the relative x of the autocorrelation based on the x input buffer.

x

input

as required

Number of inputs: One or none

y

input

as required

Number of inputs: Exactly one

minX

input

as required

Number of inputs: One or none

maxX

input

as required

Number of inputs: One or none

y

output

as required

x

output

as required

crosscorrelation

This module will calculate a crosscorrelation of two inputs. It will only calculate the part of the crosscorrelation for which the smaller buffer is entirely covered by the larger one. So with one input buffer of size n and one input of size m it will return exactly abs(m-n) values. If you need the crosscorrelation of two buffers of similar size, you will need to pad one of them with zeros first.

in

input

as not required

Number of inputs: Exactly two

out

output

as not required

differentiate

Performs a simple differentiation of a single input by calculating the difference of consecutive elements. It will write the result to the output buffer with exactly one value less than there are values in the input buffer.

in

input

as not required

Number of inputs: Exactly one

out

output

as not required

fft

This module will perform a fast fourier transform of a complex input and will write the complex result to the output buffers. For input and output the complex data is defined by two buffers re and im corresponding to the real and imaginary part. The imaginary buffer is optional and will be filled with zeros if omitted. This module will return as many values as provided by the input buffer.

re

input

as not required

Number of inputs: Exactly one

im

input

as required

Number of inputs: One or none

re

output

as not required

im

output

as required

gausssmooth

This module will smooth the data provided from the only input. The data of each point will be calculated from neighbouring points with a gaussian distribution. The width of this distribution can be controlled by the attribute sigma and is interpreted in terms of value indices. This module will output as many values as there are values in the input buffer.

sigma

attribute

optional, default: 3.0

in

input

as not required

Number of inputs: Exactly one

out

output

as not required

integrate

Performs a simple integration of a single input by summing all elements and returning each step of the summation as a value. It will write as many values as there are values in the input buffer. So, if the input is a three-value array [v1, v2, v3], the output will be [v1, v1+v2, v1+v2+v3].

in

input

as not required

Number of inputs: Exactly one

out

output

as not required

periodicity

Mathematically, this module is similar to the autocorrelation module, but is meant to analyse large amounts of data in small subsets. The output is the periodicity of each subset and the x location of this subset. The typical use is a time-based frequency analysis. You put in the recording of a (single frequency) musical melody and the output will be the frequencies as a function of time.

The x and y inputs take the data to be analyzed and you also need to define a step size dx in units of samples. This means, that the data will be split into subsets [0..dx-1], [dx..2dx-1], [2dx..3dx-1], etc. Optionally, you may define an overlap, describing the number of samples taken into the calculation from before and after the subset (hence, used in multiple subsets).

The algorithm expects the autocorrelation to be periodic. It looks for the first offset i0 at which it becomes negative and then searches for a maximum in the next positive period at 3*i0..5*i0. You may define an offset range (in samples) by setting min and/or max. If you do so, the algorithm will just search for a maximum between min and max. If you can set this range quite narrow, this will speed up the calculation vastly, but if min/max cover multiple periods, this will quite certainly be slower and give wrong results.

While all parameters are defined in samples, the resulting output time will be in units of the input x.

x

input

as required

Number of inputs: Exactly one

y

input

as required

Number of inputs: Exactly one

dx

input

as required

Number of inputs: Exactly one

overlap

input

as required

Number of inputs: One or none

min

input

as required

Number of inputs: One or none

max

input

as required

Number of inputs: One or none

time

output

as required

period

output

as required

Buffer operations

append

This module appends all the values of the input buffers to a single output buffer. The order of the buffers will match the order their values appear in the output buffer. This module will return as many value as the sum of the input buffer sizes.

in

input

as not required

type="empty" allowed

Number of inputs: At least one

out

output

as not required

count

Available since phyphox file format 1.2 (phyphox 1.0.3)

Returns the number of values in the input buffer

buffer

input

as not required

Number of inputs: Exactly one

count

output

as not required

first

Retrieves the first entry of each buffer and appends it to each output buffer.

value

input

as not required

Number of inputs: At least one

first

output

as not required

Multiple may be defined!

match

This module takes multiple inputs and match valid values to the same number of outputs. The module will go through all inputs simultaneously and only return those value for which all inputs have a finite value.

If for example input1 provides [1, 2, NaN, 4, 5] and input2 provides [11, +Inf, 13, 14], the result will be [1, 4] for output1 and [11, 14] for output2. The other value pairs (more than two inputs are allowed though) were filtered as one of both inputs was infinite, not a number ("NaN") or just did not have any more values.

in

input

as not required

Number of inputs: At least one

out

output

as not required

Multiple may be defined!

map

Available since phyphox file format 1.7 (phyphox 1.1.0)

This module takes three buffers representing x, y and z data. The data may be scattered across randomly and may be unordered. This module will be given ranges as well as a desired number of values along x and y and then rearrange the x, y, z data into a grid that is suitable to be displayed in a color map plot.

<map zMode="average">
    <input as="mapWidth" type="value">100</input>
    <input as="minX" type="value">0</input>
    <input as="maxX" type="value">10</input>
    <input as="mapHeight" type="value">100</input>
    <input as="minY" type="value">1</input>
    <input as="maxY" type="value">2</input>
    <input as="x">xData</input>
    <input as="y">yData</input>
    <input as="z">zData</input>
    <output as="x">xMapOut</output>
    <output as="y">yMapOut</output>
    <output as="z">zMapOut</output>
</map>

The example above takes xData, yData and zData and creates a grid of 100 by 100 data points covering x values from 0 to 10 and y values from 1 to 2.

zMode

attribute

optional, determines how the z data is produced from the input points, average averages all z values in a grid point, count counts the number of values (no z data has to be provided here) for each point and "sum" adds up all z values of a grid point, default: average

mapWidth

input

as required

Number of inputs: Exactly one.

minX

input

as required

Number of inputs: Exactly one.

maxX

input

as required

Number of inputs: Exactly one.

mapHeight

input

as required

Number of inputs: Exactly one.

minY

input

as required

Number of inputs: Exactly one.

maxY

input

as required

Number of inputs: Exactly one.

x

input

as required

Number of inputs: Exactly one.

y

input

as required

Number of inputs: Exactly one.

z

input

as required

Number of inputs: One or none.

x

output

as required

Number of inputs: Exactly one.

y

output

as required

Number of inputs: Exactly one.

z

output

as required

Number of inputs: Exactly one.

max

Returns the maximum and its position. This module takes at least one input y and looks for the maximum of this buffer, but may also take a second input x. If x is defined, it will return the position of this maximum in terms of the associated x value. If x is not defined, position will be the index of the maximum.

If you want to find multiple local maxima, you can set the attribute "multiple" to true. In this case a third input may be used, which provides a threshold. The algorithm will split the data into sets that are entirely above the threshold and return a maximum and position for each set.

This module will return exactly one value per call if multiple is deactivated (default).

x

input

as required

Number of inputs: One or none

y

input

as required

Number of inputs: Exactly one

threshold

input

as required

Number of inputs: One or none

max

output

as required

position

output

as required

min

Returns the minimum and its position. This module takes at least one input y and looks for the minimum of this buffer, but may also take a second input x. If x is defined, it will return the position of this minimum in terms of the associated x value. If x is not defined, position will be the index of the minimum.

If you want to find multiple local minima, you can set the attribute "multiple" to true. In this case a third input may be used, which provides a threshold. The algorithm will split the data into sets that are entirely above the threshold and return a minimum and position for each set.

This module will return exactly one value per call if multiple is deactivated (default).

x

input

as required

Number of inputs: One or none

y

input

as required

Number of inputs: Exactly one

threshold

input

as required

Number of inputs: One or none

min

output

as required

position

output

as required

rangefilter

This module takes multiple inputs and allows to set min and max limits for each of them. The module will go through all inputs simultaneously and only return those value for which all inputs fall within their set min and max range. If one input is shorter than the others, its values are set to NaN and will not trigger the filter.

Min and max have to be defined immediately after the corresponding input and are treated as a single value (last value for buffers). The outputs correspond to the order of the inputs. Here multiple outputs can be defined with the same name!

In the following example in1 will trigger the filter if not in the range of 0 and 42, in2 will not trigger the filter at all (but if in1 or in3 trigger the filter only corresponding elements will be returned) and in3 will trigger the filter if the value is larger than the value in the buffer "limit". The results will be written to the buffers "out1", "out2" and "out3".

<rangefilter>
    <input>in1</input>
    <input as="min" type="value">0</input>
    <input as="max" type="value">42</input>
    <input>in2</input>
    <input>in3</input>
    <input as="max">limit</input>
    <output>out1</output>
    <output>out2</output>
    <output>out3</output>
</rangefilter>

in

input

as not required

Number of inputs: At least one

min

input

as required

Number of inputs: One or none per in input. This always refers to the previously defined in buffer.

max

input

as required

Number of inputs: One or none per in input. This always refers to the previously defined in buffer.

out

output

as not required

Multiple may be defined!

reduce

Available since phyphox file format 1.7 (phyphox 1.1.0)

This module takes a buffer with multiple values and reduces the number of items by a given (integer) factor. It distinguishes between x and y values and allows for different strategies like summing or averaging values which fall into a single value. A factor smaller than 1 can be used to inflate the size, but in this case the module will simply duplicate each item, so each item occurs round(1/factor) times.

<reduce averageX="false" averageY="false" sumY="false">
    <input as="factor" type="value">2</input>
    <input as="x">xBuffer</input>
    <input as="y">yBuffer</input>
    <output as="x">out1</output>
    <output as="y">out2</output>
</reduce>

averageX

attribute

optional, x values will be averaged to produce x output values, default: false

averageY

attribute

optional, y values will be averaged to produce y output values, default: false

sumY

attribute

optional, the y output values will be the sum of the original y value, default: false

factor

input

as required

Number of inputs: Exactly one.

x

input

as required

Number of inputs: Exactly one.

y

input

as required

Number of inputs: One or none.

x

output

as required

Number of inputs: Exactly one.

y

output

as required

Number of inputs: One or none.

subrange

This module takes multiple inputs and returns all values within a given index range. This is much faster than using the rangefilter module for this purpose. The range is set using the inputs from (inclusive) and to (exclusive). Optionally, instead of setting to, you can set length, defining the total number of values returned after from.

<subrange>
    <input as="from" type="value">0</input>
    <input as="to">countBuffer</input>
    <input>in1</input>
    <input>in2</input>
    <output>out1</output>
    <output>out2</output>
</subrange>

from

input

as required

Number of inputs: One or none. Defaults to 0

to

input

as required

Number of inputs: One or none. Defaults to length of input

length

input

as required

Number of inputs: One or none. Defaults to length of input, supersedes to

in

input

as not required

Number of inputs: At least one

out

output

as not required

Multiple may be defined!

threshold

This module takes at least one input y and looks for position at which the values cross a given threshold. the input threshold is interpreted as a single value (last added element). This module may also take a third input x. If x is defined, it will return the position of the crossing in terms of the associated x value. If x is not defined, position will be the index of the crossing.

You can also define the attribute falling as true to search for a crossing from larger to smaller values.

This module will return exactly one value per call.

falling

attribute

optional, default: false

x

input

as required

Number of inputs: One or none

y

input

as required

Number of inputs: Exactly one

threshold

input

as required

Number of inputs: One or none (defaults to 0.0)

position

output

as not required

Data genreation

const

This module will initialize a buffer to a constant value. Both inputs are optional and without any inputs it will fill the entire buffer with zero. If value is set, the buffer gets filled with this value and if length is set, only 'length values will be initialized. (This is usefull in combination with the append module to zero-pad a buffer.)

value

input

as required

Number of inputs: One or none

length

input

as required

Number of inputs: One or none

out

output

as not required

ramp

This module will create a ramp of values, i.e. a linear range of values. This is very usefull to create time bases for example for audio recordings. The module takes as inputs start, stop and the optional length. It will make that the first value is exactly start and the last value is stop. It will return length values or if length is not provided as many values as the size of the output buffer.

start

input

as required

Number of inputs: Exactly one

stop

input

as required

Number of inputs: Exactly one

length

input

as required

Number of inputs: One or none

out

output

as not required

timer

Simple module which just outputs the (fractional) seconds that have past since the first analysis run started and the current analysis run began.

out

output

as not required

Logic

if

Available since phyphox file format 1.3 (phyphox 1.0.4)

The if module is the phyphox equivalent to the if-statement of a programming language. It takes two inputs a and b and will behave differently depending on the relation of the last values found there. By changing the attributes less, equal or greater, you can decide whether you are looking for a < b, a = b or a > b, respectively. If the relation is true, the if-module will write the data from the input true to the output, otherwise it will write the data from the input false. If you enable multiple attributes, the input true is used if any of them is fulfilled, so if you enable less and equal, a <= b will write the true input to the output, while a > b writes the false input.

Since version 1.4 (phyphox 1.0.6) you may set an input to be of the type empty. Effectively, this does not change the output as nothing is written, but can make sense in combination with setting the output to clear. In this case, the if module behaves somewhat special as it only clears its output if a matching input is connected. For example if you set the true input to empty, do not connect the false input and set the output to clear, it will only clear the output if the condition is true, but leaves it alone otherwise. This can be used as a reset condition. Note, that since the visual editor does not support reusing buffers, you probably cannot do this there in a reasonable way...

less

attribute

optional, default: false

equal

attribute

optional, default: false

greater

attribute

optional, default: false

a

input

as not required

Number of inputs: Exactly one

b

input

as not required

Number of inputs: Exactly one

true

input

as not required

type="empty" allowed

Number of inputs: Exactly one

false

input

as not required

type="empty" allowed

Number of inputs: Exactly one

out

output

as not required