Math Operations¶
Note
< > = Required user input.
[ ] = Optional user input.
[PyDV]: = Python Data Visualizer command-line prompt.
abs¶
Take the absolute value of the y values of the curves. Modifies the existing curve.
[PyDV]: abs <curve-list>
absx¶
Take the absolute value of the x values of the curves. Modifies the existing curve.
[PyDV]: absx <curve-list>
add¶
Take the sum of curves. If the optional value is specified it will add the y-values of the curves by value (equivalent to using the dy command). Shortcut: +
Note
Adding curves by a number modifies the curve. If you want to create a new curve then copy the original curve first using the copy command.
[PyDV]: add <curve-list> [value]
add_h¶
Adds curves that have been read from a file but not yet plotted. list-of-menu-numbers are the index values displayed in the first column of the menu command.
[PyDV]: add_h <list-of-menu-numbers>
average¶
Average the specified curvelist over the intersection of their domains.
[PyDV]: average <curve-list>
convolve¶
Computes the convolution of the two given curves. This is similar to the slower convolc method in ULTRA that uses direct integration and minimal interpolations. Shortcut: convol
[PyDV]: convolve <curve1> <curve2> [points]
convolveb¶
Computes the convolution of the two given curves and normalizing the second curve by the area under the curve. This computes the integrals directly which avoid padding and aliasing problems associated with FFT methods (it is however slower). Shortcut: convolb
[PyDV]: convolveb <curve1> <curve2> [points]
convolvec¶
Computes the convolution of the two given curves with no normalization. This computes the integrals directly which avoid padding and aliasing problems associated with FFT methods (it is however slower). Shortcut: convolb
[PyDV]: convolveb <curve1> <curve2> [points]
divide¶
Take quotient of curves. If the optional value is specified it will divide the y-values of the curves by value (equivalent to using the divy command). Shortcuts: /, div
Note
Dividing curves by a number modifies the curve. If you want to create a new curve then copy the original curve first using the copy command.
[PyDV]: divide <curve-list> [value]
divide_h¶
Divides curves that have been read from a file but not yet plotted. list-of-menu-numbers are the index values displayed in the first column of the menu command.
[PyDV]: divide_h <list-of-menu-numbers>
error-bar¶
Plot error bars on the given curve.
[PyDV]: errorbar <curve> <y-error-curve> <y+error-curve> [x-error-curve x+error-curve] [point-skip]
errorrange¶
Plot shaded error region on given curve, Shortcut: error-range
[PyDV]: errorrange <curve> <y-error-curve> <y+error-curve>
fft¶
Compute the one-dimensional discrete Fourier Transform for the y-values of the curves.
[PyDV]: fft <curve-list>
fftx¶
Compute the one-dimensional discrete Fourier Transform for the x-values of the curves.
[PyDV]: fftx <curve-list>
gaussian¶
Generate a gaussian function.
[PyDV]: gaussian <amplitude> <width> <center> [<# points> [<# half-widths>]]
L1¶
Makes new curve that is the L1 norm of two args; the L1 norm is integral( |curve1 - curve2| ) over the interval [xmin,xmax]. Also prints value of integral to command-line.
[PyDV]: L1 <curve1> <curve2> [<xmin> <xmax>]
L2¶
Makes new curve that is the L2 norm of two args; the L2 norm is integral( (curve1 - curve2)**2 )**(1/2) over the interval [xmin,xmax]. Also prints value of integral to command-line.
[PyDV]: L2 <curve1> <curve2> [<xmin> <xmax>]
log¶
Take the natural logarithm of the y values of the curves. If the optional argument keep-neg-vals is set to false, then zero and negative y-values will be discarded. keep-neg-vals is true by default. Shortcut: ln
[PyDV]: log <curve-list> [keep-neg-vals: True | False]
logx¶
Take the natural logarithm of the x values of the curves. If the optional argument keep-neg-vals is set to false, then zero and negative x-values will be discarded. keep-neg-vals is true by default. Shortcut: lnx
[PyDV]: logx <curve-list> [keep-neg-vals: True | False]
log10¶
Take the base 10 logarithm of the y values of the curves. If the optional argument keep-neg-vals is set to false, then zero and negative y-values will be discarded. keep-neg-vals is true by default.
[PyDV]: log10 <curve-list> [keep-neg-vals: True | False]
log10x¶
Take the base 10 logarithm of the x values of the curves. If the optional argument keep-neg-vals is set to false, then zero and negative y-values will be discarded. keep-neg-vals is true by default.
[PyDV]: log10x <curve-list> [keep-neg-vals: True | False]
makeintensive - 2.4.2¶
Set the y-values such that y[i] = y[i] / (x[i+1] - x[i]). Shortcut: mkint
[PyDV]: makeintensive <curve-list>
makeextensive - 2.4.2¶
Set the y-values such that y[i] = y[i] * (x[i+1] - x[i]). Shortcut: mkext
[PyDV]: makeextensive <curve-list>
multiply¶
Take the product of curves. If the optional value is specified it will multiply the y-values of the curves by value (equivalent to using the my command). Shortcuts: *, mult
Note
Multiplying curves by a number modifies the curve. If you want to create a new curve then copy the original curve first using the copy command.
[PyDV]: multiply <curve-list> [value]
multiply_h¶
Multiplies curves that have been read from a file but not yet plotted. list-of-menu-numbers are the index values displayed in the first column of the menu command.
[PyDV]: multiply_h <list-of-menu-numbers>
norm¶
Makes a new curve that is the norm of two args. Also prints the value of the integral to command line.
[PyDV]: norm <curve> <curve> <p> <xmin> <xmax>
Note
The p-norm is (integral( (curve1 - curve2)**p )**(1/p) over the interval [xmin, xmax], where p = order.
powa¶
Raise a fixed value, a, to the power of the y values of the curves.
[PyDV]: powa <curve-list> <a>
powax¶
Raise a fixed value, a, to the power of the x values of the curves.
[PyDV]: powax <curve-list> <a>
subtract¶
Take the difference of curves. A single curve can be specified, resulting in the negating of its y-values. If the optional value is specified it will subtract the y-values of the curves by value (similar to using the dy command). Shortcuts: –, sub
Note
Subtracting curves by a number modifies the curve. If you want to create a new curve then copy the original curve first using the copy command.
[PyDV]: subtract <curve-list> [value]
subtract_h¶
Subtracts curves that have been read from a file but not yet plotted. list-of-menu-numbers are the index values displayed in the first column of the menu command.
[PyDV]: subtract_h <list-of-menu-numbers>
xmax¶
Filter out points in curves whose x-values greater than limit
[PyDV]: xmax <curve-list> <limit>
y0¶
Take the zeroth order Bessel function of the second kind of the y values of the curves.
[PyDV]: y0 <curve-list>
y0x¶
Take the zeroth order Bessel function of the second kind of the x values of the curves.
[PyDV]: y0x <curve-list>
y1¶
Take the first order Bessel function of the second kind of the y values of the curves.
[PyDV]: y1 <curve-list>
y1x¶
Take the first order Bessel function of the second kind of the x values of the curves.
[PyDV]: y1x <curve-list>
ymax¶
Filter out points in curves whose y-values greater than limit
[PyDV]: ymax <curve-list> <limit>
yminmax¶
Trim the selected curves. Shortcut: ymm
[PyDV]: yminmax <curve-list> <low-limit> <high-lim>
yn¶
Take the nth order Bessel function of the second kind of y values of curves
[PyDV]: yn <curve-list> <n>
ynx¶
Take the nth order Bessel function of the second kind of x values of curves
[PyDV]: ynx <curve-list> <n>
diffMeasure¶
Compare two curves. For the given curves a fractional difference measure and its average is computed
[PyDV]: diffMeasure <curve1> <curve2> [tolerance]
fit¶
Make new curve that is polynomial fit to argument. n=1 by default, logy means take log(y-values) before fitting, logx means take log(x-values) before fitting
[PyDV]: fit <curve> [n] [logx] [logy]
integrate¶
Compute the definite integral of each curve in the list over the specified domain. Shortcut: int
[PyDV]: integrate <curve-list> [low-limit high-limit]
span¶
Generates a straight line of slope 1 and y intercept 0 in the specified domain with an optional number of points
[PyDV]: span <xmin> <xmax> [points]
vs¶
Plot the range of the first curve against the range of the second curve
[PyDV]: vs <curve1> <curve2>