comparison filter/scales.c @ 0:5242703e91d3 tip

Initial checkin for AIM92 aimR8.2 (last updated May 1997).

+/*
+    Copyright (c) Applied Psychology Unit, Medical Research Council. 1988, 1989
+    ===========================================================================
+
+    Permission to use, copy, modify, and distribute this software without fee 
+    is hereby granted for research purposes, provided that this copyright 
+    notice appears in all copies and in all supporting documentation, and that 
+    the software is not redistributed for any fee (except for a nominal shipping 
+    charge). Anyone wanting to incorporate all or part of this software in a
+    commercial product must obtain a license from the Medical Research Council.
+
+    The MRC makes no representations about the suitability of this 
+    software for any purpose.  It is provided "as is" without express or implied 
+    warranty.
+ 
+    THE MRC DISCLAIMS ALL WARRANTIES WITH REGARD TO THIS SOFTWARE, INCLUDING 
+    ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO EVENT SHALL THE
+    A.P.U. BE LIABLE FOR ANY SPECIAL, INDIRECT OR CONSEQUENTIAL DAMAGES OR ANY 
+    DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN 
+    AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF 
+    OR IN CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+*/
+
+/*
+	scales.c
+	========
+
+    generates double arrays of numbers spaced on arbitrary frequency scales
+
+*/
+
+#include <math.h>
+
+#ifndef  _STITCH_H_
+#include "stitch.h"
+#endif
+#ifndef  _SCALES_H_
+#include "scales.h"
+#endif
+
+double *GenerateScale( min, max, density, base, inverse )
+double min, max, density, base, (*inverse)() ;
+{
+    unsigned n_scale = NumberOnScale( min, max, density, base ) ;
+    double *scale = NewArray( double, n_scale+1, "for scale in scales.c" ) ;
+    double scale_start ;
+    int i ;
+
+    if( min != max ) {
+
+	scale_start = base - floor( ( base - min ) * density ) / density ;
+
+	/* fill array scale points 1./density apart */
+
+	for( i=0 ; i < n_scale  ; i++ )
+	    scale[ i ] = scale_start + i / density   ;
+
+	scale[ i++ ] = 0. ;
+    }
+    else {
+	scale[0] = min ;
+	scale[1] = 0.  ;
+    }
+
+	/* convert scale space back to units required */
+
+    if( inverse != (double ( * )()) 0 )
+	for( i=0 ; i < n_scale  ; i++ )
+	    scale[ i ] = inverse( scale[ i ] ) ;
+
+    return ( scale ) ;
+}
+
+int NumberOnScale( min, max, density, base )
+double min, max, density, base ;
+{
+    if( min != max )
+	return ( ( int ) ( ( floor( ( base - min ) * density ) + 1. + ( floor( ( max - base ) * density ) ) ) ) ) ;
+    else
+	return ( 1 ) ;
+}
+
+double *NumberedScale( min, max, channels, inverse )
+double min, max ;
+int channels ;
+double (*inverse)() ;
+{
+    DeclareNewArray( double, scale, channels+1, "for scale in scales.c" ) ;
+    int chan ;
+
+    scale[ 0 ] = min ;
+    for( chan=1 ; chan < channels  ; chan++ )
+	scale[ chan ] = min + chan * (max-min) / ( channels - 1 ) ;
+
+    if( inverse != (double ( * )()) 0 )
+	for( chan=0 ; chan < channels  ; chan++ )
+	    scale[ chan ] = inverse( scale[ chan ] ) ;
+
+    scale[ channels ] = 0. ;
+
+    return ( scale ) ;
+}