Hello,<br><br>I was profiling the performance of the changes that happened in r9112, and it turned out to be very significant to pass and evaluate integers in the prepared expression. Sticking with float8 values for the x and y positions of the pixel contain significant performance benefits (although counter-intuitive).<br>
<br>I've changed the x and y positions in 1 raster map algebra back to float values for performance reasons.<br><br>These are my metrics for running 5 sets of 10 rasters, each 500x500 pixels, from one of the SRTM tiles linked to by the WKTRaster tutorial page. Times are in milliseconds. The first column is revision 9112 (removal of strstr in the pixel loop, using integer as x and y pixel values), the second column is that same revision (with a modification to use float8 instead of int32 for x and y pixel coordinates), the third column is revision 9111 (using strstr in the pixel loop), the fourth column is the incorporation of this change into the HEAD revision as of this morning (more memory allocations have been moved out of the pixel loop).<br>
<br>
<table frame="VOID" rules="NONE" border="0" cellspacing="0" cols="4">
        <colgroup><col width="86"><col width="86"><col width="86"><col width="86"></colgroup>
        <tbody>
                <tr>
                        <td style="text-align:right" height="18" width="86">r9112</td>
                        <td style="text-align:right" width="86">r9112-int</td>
                        <td style="text-align:right" width="86">r9111</td>
                        <td style="text-align:right" width="86">r9137</td>
                </tr>
                <tr>
                        <td height="17" align="RIGHT">9839.746</td>
                        <td align="RIGHT">8473.403</td>
                        <td align="RIGHT">9094.589</td>
                        <td align="RIGHT">7820.646</td>
                </tr>
                <tr>
                        <td height="18" align="RIGHT">6228.067</td>
                        <td align="RIGHT">5329.813</td>
                        <td align="RIGHT">5763.88</td>
                        <td align="RIGHT">4738.372</td>
                </tr>
                <tr>
                        <td height="17" align="RIGHT">8749.516</td>
                        <td align="RIGHT">7441.936</td>
                        <td align="RIGHT">7893.893</td>
                        <td align="RIGHT">6866.745</td>
                </tr>
                <tr>
                        <td height="17" align="RIGHT">13618.762</td>
                        <td align="RIGHT">11254.392</td>
                        <td align="RIGHT">12177.314</td>
                        <td align="RIGHT">10780.401</td>
                </tr>
                <tr>
                        <td height="17" align="RIGHT">6233.851</td>
                        <td align="RIGHT">5442.746</td>
                        <td align="RIGHT">5730.231</td>
                        <td align="RIGHT">4767.192</td>
                </tr>
        </tbody>
</table>
<br><br>Thanks,<br>Zwarg