make_lwork: Round lwork for float

Functions
magmaFloatComplex	magma_cmake_lwork (magma_int_t lwork)
	This deals with a subtle bug with returning lwork as a Float.
double	magma_dmake_lwork (magma_int_t lwork)
	This deals with a subtle bug with returning lwork as a Float.
float	magma_smake_lwork (magma_int_t lwork)
	This deals with a subtle bug with returning lwork as a Float.
magmaDoubleComplex	magma_zmake_lwork (magma_int_t lwork)
	This deals with a subtle bug with returning lwork as a Float.

Detailed Description

Function Documentation

magma_cmake_lwork()

magmaFloatComplex magma_cmake_lwork

(

magma_int_t

lwork

)

This deals with a subtle bug with returning lwork as a Float.

If lwork > 2**24, then it will get rounded as a Float; we need to ensure it is rounded up instead of down, by multiplying by 1.+eps in Double precision:

float( 16777217            ) == 16777216
float( 16777217 * (1.+eps) ) == 16777218

where eps is Single precision machine epsilon. (Could use 1+2*eps in Single precision, but that can add more than necesary.) If lwork > 2**53, rounding would happen in Double, too, but that's 94M x 94M!

Parameters

[in]

lwork

Workspace size.

Returns

lwork, converted to magmaFloatComplex and rounded up slightly if necesary so that returned lwork >= input lwork.

magma_dmake_lwork()

double magma_dmake_lwork

(

magma_int_t

lwork

)

This deals with a subtle bug with returning lwork as a Float.

If lwork > 2**24, then it will get rounded as a Float; we need to ensure it is rounded up instead of down, by multiplying by 1.+eps in Double precision:

float( 16777217            ) == 16777216
float( 16777217 * (1.+eps) ) == 16777218

where eps is Single precision machine epsilon. (Could use 1+2*eps in Single precision, but that can add more than necesary.) If lwork > 2**53, rounding would happen in Double, too, but that's 94M x 94M!

Parameters

[in]

lwork

Workspace size.

Returns

lwork, converted to double and rounded up slightly if necesary so that returned lwork >= input lwork.

magma_smake_lwork()

float magma_smake_lwork

(

magma_int_t

lwork

)

This deals with a subtle bug with returning lwork as a Float.

If lwork > 2**24, then it will get rounded as a Float; we need to ensure it is rounded up instead of down, by multiplying by 1.+eps in Double precision:

float( 16777217            ) == 16777216
float( 16777217 * (1.+eps) ) == 16777218

where eps is Single precision machine epsilon. (Could use 1+2*eps in Single precision, but that can add more than necesary.) If lwork > 2**53, rounding would happen in Double, too, but that's 94M x 94M!

Parameters

[in]

lwork

Workspace size.

Returns

lwork, converted to float and rounded up slightly if necesary so that returned lwork >= input lwork.

magma_zmake_lwork()

magmaDoubleComplex magma_zmake_lwork

(

magma_int_t

lwork

)

This deals with a subtle bug with returning lwork as a Float.

If lwork > 2**24, then it will get rounded as a Float; we need to ensure it is rounded up instead of down, by multiplying by 1.+eps in Double precision:

float( 16777217            ) == 16777216
float( 16777217 * (1.+eps) ) == 16777218

where eps is Single precision machine epsilon. (Could use 1+2*eps in Single precision, but that can add more than necesary.) If lwork > 2**53, rounding would happen in Double, too, but that's 94M x 94M!

Parameters

[in]

lwork

Workspace size.

Returns

lwork, converted to magmaDoubleComplex and rounded up slightly if necesary so that returned lwork >= input lwork.