One of the types of objects in Praat. A Matrix object represents a function z (x, y) on the domain [x_{min}, x_{max}] × [y_{min}, y_{max}]. The domain has been sampled in the x and y directions with constant sampling intervals (dx and dy) along each direction. The samples are thus z [i_{y}] [i_{x}], i_{x} = 1 ... n_{x}, i_{y} = 1 ... n_{y}. The samples represent the function values z (x_{1} + (ix  1) dx, y_{1} + (iy  1) dy).
Matrix commands
Creation:

• Create Matrix...

• Create simple Matrix...

• Read from file...

• Read Matrix from raw text file...

• Read Matrix from LVS AP file...
Drawing:

• Matrix: Draw rows...

• Matrix: Draw contours...

• Matrix: Paint contours...

• Matrix: Paint cells...

• Matrix: Scatter plot...

• Matrix: Draw as squares...

• Matrix: Draw value distribution...

• Matrix: Paint surface...
Modification:

• Matrix: Formula...

• Matrix: Scale...
Inside a Matrix object
With Inspect, you will see the following attributes.

xmin, xmax ≥ xmin

x domain.

nx ≥ 1

number of columns.

dx > 0.0

distance between columns.

x1

x value associated with first column.

ymin, ymax ≥ ymin

y domain.

ny ≥ 1

number of rows.

dy > 0.0

distance between rows.

y1

y value associated with first row.

z [1..ny] [1..nx]

The sample values.
After creation of the Matrix, xmin, xmax, ymin, ymax, nx, ny, dx, dy, x1, and y1 do not usually change. The contents of z do.
Normally, you will want xmin ≤ x1 and xmax ≥ x1 + (nx  1) dx.
Example: simple matrix
If a simple matrix has x equal to column number and y equal to row number, it has the following attributes:

xmin = 1; xmax = nx; dx = 1; x1 = 1;

ymin = 1; ymax = ny; dy = 1; y1 = 1;
Example: sampled signal
If the matrix represents a sampled signal of 1 second duration with a sampling frequency of 10 kHz, it has the following attributes:

xmin = 0.0; xmax = 1.0; nx = 10000 ; dx = 1.0·10^{4}; x1 = 0.5·10^{4};

ymin = 1; ymax = 1; ny = 1; dy = 1; y1 = 1;
Example: complex signal
If the matrix represents a complex spectrum derived with an FFT from the sound of example 2, it has the following attributes:

xmin = 0.0; xmax = 5000.0; nx = 8193 ; dx = 5000.0 / 8192; x1 = 0.0;

ny = 2 (real and imaginary part);

ymin = 1 (first row, real part);

ymax = 2 (second row, imaginary part);

dy = 1; y1 = 1; (so that y is equal to row number)
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