nag_dge_load (f16qhc) (PDF version)
f16 Chapter Contents
f16 Chapter Introduction
NAG Library Manual

NAG Library Function Document

nag_dge_load (f16qhc)

 Contents

    1  Purpose
    7  Accuracy

1  Purpose

nag_dge_load (f16qhc) initializes a real general matrix.

2  Specification

#include <nag.h>
#include <nagf16.h>
void  nag_dge_load (Nag_OrderType order, Integer m, Integer n, double alpha, double diag, double a[], Integer pda, NagError *fail)

3  Description

nag_dge_load (f16qhc) forms the real m by n general matrix A given by
aij= d if i=j α if ij .  

4  References

Basic Linear Algebra Subprograms Technical (BLAST) Forum (2001) Basic Linear Algebra Subprograms Technical (BLAST) Forum Standard University of Tennessee, Knoxville, Tennessee http://www.netlib.org/blas/blast-forum/blas-report.pdf

5  Arguments

1:     order Nag_OrderTypeInput
On entry: the order argument specifies the two-dimensional storage scheme being used, i.e., row-major ordering or column-major ordering. C language defined storage is specified by order=Nag_RowMajor. See Section 3.2.1.3 in the Essential Introduction for a more detailed explanation of the use of this argument.
Constraint: order=Nag_RowMajor or Nag_ColMajor.
2:     m IntegerInput
On entry: m, the number of rows of the matrix A.
Constraint: m0.
3:     n IntegerInput
On entry: n, the number of columns of the matrix A.
Constraint: n0.
4:     alpha doubleInput
On entry: the value, α, to be assigned to the off-diagonal elements of A.
5:     diag doubleInput
On entry: the value, d, to be assigned to the diagonal elements of A.
6:     a[dim] doubleOutput
Note: the dimension, dim, of the array a must be at least
  • max1,pda×n when order=Nag_ColMajor;
  • max1,m×pda when order=Nag_RowMajor.
If order=Nag_ColMajor, Aij is stored in a[j-1×pda+i-1].
If order=Nag_RowMajor, Aij is stored in a[i-1×pda+j-1].
On exit: the m by n general matrix A.
7:     pda IntegerInput
On entry: the stride separating row or column elements (depending on the value of order) of the matrix A in the array a.
Constraint: pdamax1,m.
8:     fail NagError *Input/Output
The NAG error argument (see Section 3.6 in the Essential Introduction).

6  Error Indicators and Warnings

NE_ALLOC_FAIL
Dynamic memory allocation failed.
See Section 3.2.1.2 in the Essential Introduction for further information.
NE_BAD_PARAM
On entry, argument value had an illegal value.
NE_INT
On entry, m=value.
Constraint: m0.
On entry, n=value.
Constraint: n0.
On entry, pda=value.
Constraint: pdamax1,m.
On entry, pda=value.
Constraint: pdamax1,n.
NE_INT_2
On entry, pda=value, m=value.
Constraint: pdamax1,m.
NE_INTERNAL_ERROR
An internal error has occurred in this function. Check the function call and any array sizes. If the call is correct then please contact NAG for assistance.
An unexpected error has been triggered by this function. Please contact NAG.
See Section 3.6.6 in the Essential Introduction for further information.
NE_NO_LICENCE
Your licence key may have expired or may not have been installed correctly.
See Section 3.6.5 in the Essential Introduction for further information.

7  Accuracy

The BLAS standard requires accurate implementations which avoid unnecessary over/underflow (see Section 2.7 of Basic Linear Algebra Subprograms Technical (BLAST) Forum (2001)).

8  Parallelism and Performance

Not applicable.

9  Further Comments

None.

10  Example

This example initializes a real general matrix, A, with diagonal off-diagonal value, α=1.23 and diagonal value, d=3.45.

10.1  Program Text

Program Text (f16qhce.c)

10.2  Program Data

Program Data (f16qhce.d)

10.3  Program Results

Program Results (f16qhce.r)


nag_dge_load (f16qhc) (PDF version)
f16 Chapter Contents
f16 Chapter Introduction
NAG Library Manual

© The Numerical Algorithms Group Ltd, Oxford, UK. 2015