Name

sconv_periodic_ext, dconv_periodic_ext, cconv_periodic_ext, zconv_periodic_ext − Extended periodic convolution

FORMAT

status = {S,D,C,Z}CONV_PERIODIC_EXT (x, nx_stride, y, ny_stride, out, out_stride, n, n_out_start, n_out_end, add_flag, scale_flag, scale, scale_stride)

Arguments

xreal∗4 | real∗8 | complex∗8 | complex∗16
On entry, an array containing the data to be convolved.
On exit, x is unchanged. 

nx_strideinteger∗4
Distance between elements in the X array; nx_stride > 0

yreal∗4 | real∗8 | complex∗8 | complex∗16
On entry, an array containing the convolution or "filter" function which is to be convolved with the data from the X array.
On exit, y is unchanged. 

ny_strideinteger∗4
Distance between elements in the Y array; ny_stride > 0

outreal∗4 | real∗8 | complex∗8 | complex∗16
On entry, a one-dimensional array OUT of length n.
On exit, out contains the convoluted data. 

out_strideinteger∗4
Specifies the distance between elements in the OUT array; out_stride > 0

ninteger∗4
Specifies the number of values to be operated on; n > 0

n_out_start, n_out_end
integer∗4
Specifies the range of coefficients computed; n_out_end > n_out_start.  The OUT array has zero values for indices less than 0 or greater than
 n - 1 .

For example, in the case of n = 100, the locations range from 0 through 99. If you specify n_out_start = 5 and n_out_end = 10, the convolution function generates numbers for OUT(5) through OUT(10) and puts the results in location 0 through 5 of the OUT array. 

You can also specify a range that is larger than the array. For example, using the same input array, you can specify n_out_start = -10 and n_out_end = 200.  The convolution function can generate values OUT(0) through OUT(99),  putting them in location 10 through 109 of the output array. The locations outside of the range do not get null values; they are not affected. 

add_flaglogical∗4
Defines the operation of the convolution to add output to an existing OUT array, without overwriting it.

TRUE: Add the result of the operation to OUT array. 

FALSE: Overwrite the existing OUT array. 

scale_flaglogical∗4
Defines the operation of the convolution to scale the output.

TRUE: Scale the output. 

FALSE: Do not scale. 

scalereal∗4 | real∗8 | complex∗8 | complex∗16
The value by which to scale the output.

scale_strideinteger∗4
Defines how the scale operation is performed. scale_stride# 0:

 = 0 : Scale by a scalar value

 > 0: Scale by a vector, used as the stride of scale

Description

The _CONV_PERIODIC_EXT functions compute the periodic convolution with options to control the result. 

Return Values

0DXML_SUCCESS()

8DXML_ILL_N_RANGE()

13DXML_BAD_STRIDE()

Example

  INCLUDE ’{file_location}DXMLDEF.FOR’
  INTEGER∗4 N,STATUS
  REAL∗8 A(100),B(100),C(6),SCALE_VALUE
  SCALE_VALUE = 2.0
  STATUS = DCONV_PERIODIC_EXT(A,1,B,1,C,1,100,5,10,.FALSE.,.TRUE.,SCALE_VALUE,0)

This FORTRAN code computes six values of a periodic convolution of two vector, C(5) to C(10),  of double-precision real numbers, a and b, with length of 100. The result is scaled by  2.0 and stored in c with length of 6.