Class: KissFFT

Inherits:
Object
  • Object
show all
Defined in:
ext/kissfft/main.c

Class Method Summary collapse

Class Method Details

.fftr(r_nfft, r_rate, r_buckets, r_data) ⇒ Object


34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
# File 'ext/kissfft/main.c', line 34

static VALUE
rbkiss_s_fftr(VALUE class, VALUE r_nfft, VALUE r_rate, VALUE r_buckets, VALUE r_data)
{
	kiss_fftr_cfg cfg=NULL;
	kiss_fft_scalar *tbuf;
	kiss_fft_cpx *fbuf;
	float *mag2buf;
	int i;
	int avgctr=0;
	int nrows=0;

	int nfft;
	int rate;
	int navg;
	int nfreqs;

	int inp_len;
	int inp_idx;

	// Result set
	VALUE res;
	VALUE tmp;
	VALUE set;
	res = rb_ary_new();

	if(TYPE(r_nfft) != T_FIXNUM) {
		return Qnil;
	}
	nfft=NUM2INT(r_nfft);

	if(TYPE(r_rate) != T_FIXNUM) {
		return Qnil;
	}
	rate=NUM2INT(r_rate);

	if(TYPE(r_buckets) != T_FIXNUM) {
		return Qnil;
	}
	navg=NUM2INT(r_buckets);

	if(TYPE(r_data) != T_ARRAY) {
		return Qnil;
	}

	if(RARRAY_LEN(r_data) == 0) {
		return Qnil;
	}

	if(TYPE(RARRAY_PTR(r_data)[0]) != T_FIXNUM ) {
		return Qnil;
	}	

	nfreqs=nfft/2+1;

	CHECKNULL( cfg=kiss_fftr_alloc(nfft,0,0,0) );
	CHECKNULL( tbuf=(kiss_fft_scalar*)malloc(sizeof(kiss_fft_scalar)*(nfft + 2) ) );
	CHECKNULL( fbuf=(kiss_fft_cpx*)malloc(sizeof(kiss_fft_cpx)*(nfft + 2)) );
	CHECKNULL( mag2buf=(float*)malloc(sizeof(float)*(nfft + 2) ));	

	memset(mag2buf,0,sizeof(mag2buf)*nfreqs);

	inp_len = RARRAY_LEN(r_data);
	inp_idx = 0;

	while(inp_idx < inp_len) {

		// Fill tbuf with nfft samples
		for(i=0;i<nfft;i++) {
			if(inp_idx + i >= inp_len) {
				tbuf[i] = 0;
			} else {
				if(TYPE(RARRAY_PTR(r_data)[ inp_idx + i ]) != T_FIXNUM) {
					tbuf[i] = 0;
				} else {
					tbuf[i] = NUM2INT( RARRAY_PTR(r_data)[ inp_idx + i ] );
				}
			}
		}


		/* do FFT */
		kiss_fftr(cfg,tbuf,fbuf);

		for (i=0;i<nfreqs;++i) {
			mag2buf[i] += fbuf[i].r * fbuf[i].r + fbuf[i].i * fbuf[i].i;
		}

		if (++avgctr == navg) {
			float eps = 1;
			avgctr=0;
			++nrows;

			// RESULTS
			set = rb_ary_new();
			for (i=0;i<nfreqs;++i) {
				float pwr = 10 * log10( mag2buf[i] / navg + eps );
				tmp = rb_ary_new();
				rb_ary_push(tmp, rb_float_new( (float)i * ( ( (float)rate / 2) / (float)nfreqs) ));
				rb_ary_push(tmp, rb_float_new( pwr));
				rb_ary_push(set, tmp);
			}
			rb_ary_push(res, set);
			memset(mag2buf,0,sizeof(mag2buf[0])*nfreqs);
		}
		inp_idx += nfft;
	}

	free(cfg);
	free(tbuf);	
	free(fbuf);
	free(mag2buf);
	return(res);		
}

.versionObject


26
27
28
29
30
# File 'ext/kissfft/main.c', line 26

static VALUE
rbkiss_s_version(VALUE class)
{
	return rb_str_new2(KISS_VERSION);	
}