3.12.7 STFA

Method on mglGraph: void STFA (const mglData &x, const mglData &y, const mglData &re, const mglData &im, int dn, const char *sch=NULL, float zVal=NAN)

Draws spectrogram of complex array re+i*im for Fourier size of dn points at plane z=zVal. Parameter dn is arbitrary even integer. For example in 1D case, result is density plot of data res[i,j]=|\sum_d^dn exp(I*j*d)*(re[i*dn+d]+I*im[i*dn+d])|/dn with size {int(nx/dn), dn, ny}. At this array re, im parametrically depend on coordinates x, y. String sch sets the color scheme. Previous color scheme is used by default. The size of re and im must be the same. The minor dimensions of arrays x, y, re should be equal. Arrays x, y can be vectors (not matrix as re). See section Color scheme.

Method on mglGraph: void STFA (const mglData &re, const mglData &im, int dn, const char *sch=NULL, float zVal=NAN)

The same as previous with x, y equidistantly distributed in interval [Min, Max].