Class: Numo::GSL::HistogramPdf

Inherits:

Object

• Object
• Numo::GSL::HistogramPdf

Defined in:

ext/numo/gsl/histogram/gsl_histogram.c

Class Method Summary

• .new(n) ⇒ Object

  allocate instance of HistogramPdf class.

Instance Method Summary

• #init(h) ⇒ Bool

  This function initializes the probability distribution p with the contents of the histogram h.

• #n ⇒ Integer

  returns n field in gsl_histogram_pdf struct.

• #range ⇒ DFloat

  returns range field in gsl_histogram_pdf struct.

• #sample(r) ⇒ DFloat

  This function uses r, a uniform random number between zero and one, to compute a single random sample from the probability distribution p.

• #sum ⇒ DFloat

  returns sum field in gsl_histogram_pdf struct.

Class Method Details

.new(n) ⇒ Object

allocate instance of HistogramPdf class.

This function allocates memory for a probability distribution with n bins and returns a pointer to a newly initialized gsl_histogram_pdf struct. If insufficient memory is available a null pointer is returned and the error handler is invoked with an error code of GSL_ENOMEM.

Parameters:

• n (Integer) —

  parameter

# File 'ext/numo/gsl/histogram/gsl_histogram.c', line 996

static VALUE
histogram_pdf_s_new(VALUE self, VALUE v1)
{
    gsl_histogram_pdf *w;
    w = gsl_histogram_pdf_alloc(NUM2SIZET(v1));
    if (!w) {
        rb_raise(rb_eNoMemError,"fail to allocate struct");
    }
    return TypedData_Wrap_Struct(cHistogramPdf, &histogram_pdf_data_type, (void*)w);
}

Instance Method Details

#init(h) ⇒ Bool

This function initializes the probability distribution p with the contents of the histogram h. If any of the bins of h are negative then the error handler is invoked with an error code of GSL_EDOM because a probability distribution cannot contain negative values.

Parameters:

• h (HistogramPdf)

Returns:

• (Bool)

# File 'ext/numo/gsl/histogram/gsl_histogram.c', line 1021

static VALUE
histogram_pdf_init(VALUE self, VALUE v1)
{
    int stat;
    gsl_histogram_pdf *w;
    gsl_histogram *w1;

    TypedData_Get_Struct(self, gsl_histogram_pdf, &histogram_pdf_data_type, w);
    TypedData_Get_Struct(v1, gsl_histogram, &histogram_data_type, w1);

    stat = gsl_histogram_pdf_init(w, w1);
    return (stat) ? Qtrue: Qfalse;
}

#n ⇒ Integer

returns n field in gsl_histogram_pdf struct.

Returns:

• (Integer)

# File 'ext/numo/gsl/histogram/gsl_histogram.c', line 909

static VALUE
histogram_pdf_n(VALUE self)
{
    gsl_histogram_pdf *w;

    TypedData_Get_Struct(self, gsl_histogram_pdf, &histogram_pdf_data_type, w);

    return SIZET2NUM(w->n);
}

#range ⇒ DFloat

returns range field in gsl_histogram_pdf struct.

Returns:

• (DFloat) —

  narray of range field in gsl_histogram_pdf.

# File 'ext/numo/gsl/histogram/gsl_histogram.c', line 928

static VALUE
histogram_pdf_range(VALUE self)
{
    gsl_histogram_pdf *w;
    double *d;
    VALUE v;
    size_t n, i, shape[1];

    TypedData_Get_Struct(self, gsl_histogram_pdf, &histogram_pdf_data_type, w);

    
    shape[0] = n = w->n+1;
    

    v = rb_narray_new(cDF, 1, shape);
    d = (double*)na_get_pointer_for_write(v);
    for (i=0; i<n; i++) {
        d[i] = w->range[i];
    }
    return v;
}

#sample(r) ⇒ DFloat

This function uses r, a uniform random number between zero and one, to compute a single random sample from the probability distribution p. The algorithm used to compute the sample s is given by the following formula,

s = range[i] + delta * (range[i+1] - range[i])

where i is the index which satisfies $sum[i] \le r < sum[i+1]$ sum[i] <= r < sum[i+1] and delta is $(r - sum[i])/(sum[i+1] - sum[i])$ (r - sum[i])/(sum[i+1] - sum[i]).

Parameters:

• r (DFloat)

Returns:

• (DFloat) —

  result

# File 'ext/numo/gsl/histogram/gsl_histogram.c', line 1077

static VALUE
histogram_pdf_sample(VALUE self, VALUE v1)
{
    gsl_histogram_pdf *w;
    ndfunc_arg_in_t ain[1] = {{cDF,0}};
    ndfunc_arg_out_t aout[1] = {{cDF,0}};
    ndfunc_t ndf = {iter_histogram_pdf_sample, STRIDE_LOOP|NDF_EXTRACT, 1,1, ain,aout};

    TypedData_Get_Struct(self, gsl_histogram_pdf, &histogram_pdf_data_type, w);

    return na_ndloop3(&ndf, w, 1, v1);
}

#sum ⇒ DFloat

returns sum field in gsl_histogram_pdf struct.

Returns:

• (DFloat) —

  narray of sum field in gsl_histogram_pdf.

# File 'ext/numo/gsl/histogram/gsl_histogram.c', line 959

static VALUE
histogram_pdf_sum(VALUE self)
{
    gsl_histogram_pdf *w;
    double *d;
    VALUE v;
    size_t n, i, shape[1];

    TypedData_Get_Struct(self, gsl_histogram_pdf, &histogram_pdf_data_type, w);

    
    shape[0] = n = w->n;
    

    v = rb_narray_new(cDF, 1, shape);
    d = (double*)na_get_pointer_for_write(v);
    for (i=0; i<n; i++) {
        d[i] = w->sum[i];
    }
    return v;
}