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## Re: Fast copy of buffer data into a matrix

**From**: |
John W. Eaton |

**Subject**: |
Re: Fast copy of buffer data into a matrix |

**Date**: |
Fri, 9 Feb 2007 12:55:30 -0500 |

On 9-Feb-2007, John Swensen wrote:
| Is there a difference between:
| 1) static unit8NDArray m (dim_vector(settings.width, settings.height));
| and
| 2) static uint8NDArray m = octave_value(m1).uint8_array_value();
| ?
Yes. Is m1 a Matrix object? Assuming it is, then the first statement
creates a uint8NDArray object directly and the second takes m1 (double
values if it is a Matrix object), wraps it in an octave_value object,
then extracts a uint8NDArray object from it, requiring a type
conversion and data copying. So the second is a lot more work and
wastes space if all you really want is a uint8NDArray object.
jwe

**Fast copy of buffer data into a matrix**, *John Swensen*, `2007/02/08`
**Re: Fast copy of buffer data into a matrix**, *Nicolas Pettiaux*, `2007/02/08`
**Re: Fast copy of buffer data into a matrix**, *Muthiah Annamalai*, `2007/02/08`
**Re: Fast copy of buffer data into a matrix**, *John Swensen*, `2007/02/08`
**Re: Fast copy of buffer data into a matrix**, *John Swensen*, `2007/02/09`
**Re: Fast copy of buffer data into a matrix**, *David Bateman*, `2007/02/09`
**Re: Fast copy of buffer data into a matrix**, *John Swensen*, `2007/02/09`
**Re: Fast copy of buffer data into a matrix**,
*John W. Eaton* **<=**
**Re: Fast copy of buffer data into a matrix**, *John W. Eaton*, `2007/02/09`
**Re: Fast copy of buffer data into a matrix**, *John Swensen*, `2007/02/09`
**Re: Fast copy of buffer data into a matrix**, *John W. Eaton*, `2007/02/09`