From: Wolfgang Bangerth Date: Fri, 29 Apr 2016 19:34:10 +0000 (-0500) Subject: Add a note about evaluating point values/gradients. X-Git-Tag: v8.5.0-rc1~1066^2 X-Git-Url: https://gitweb.dealii.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=refs%2Fpull%2F2564%2Fhead;p=dealii.git Add a note about evaluating point values/gradients. Specifically, say that this is likely going to lead to heartbreak if done close to a cell boundary. --- diff --git a/include/deal.II/numerics/vector_tools.h b/include/deal.II/numerics/vector_tools.h index 6ea18791f3..f6a32858a0 100644 --- a/include/deal.II/numerics/vector_tools.h +++ b/include/deal.II/numerics/vector_tools.h @@ -2044,6 +2044,17 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the value of the finite element field either + * here or there, depending on which cell the point is found in. This + * does not matter (to within the same tolerance) if the finite element + * field is continuous. On the other hand, if the finite element in use + * is not continuous, then you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template void @@ -2057,6 +2068,17 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the value of the finite element field either + * here or there, depending on which cell the point is found in. This + * does not matter (to within the same tolerance) if the finite element + * field is continuous. On the other hand, if the finite element in use + * is not continuous, then you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template void @@ -2079,6 +2101,17 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the value of the finite element field either + * here or there, depending on which cell the point is found in. This + * does not matter (to within the same tolerance) if the finite element + * field is continuous. On the other hand, if the finite element in use + * is not continuous, then you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template typename VectorType::value_type @@ -2091,6 +2124,17 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the value of the finite element field either + * here or there, depending on which cell the point is found in. This + * does not matter (to within the same tolerance) if the finite element + * field is continuous. On the other hand, if the finite element in use + * is not continuous, then you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template typename VectorType::value_type @@ -2108,6 +2152,17 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the value of the finite element field either + * here or there, depending on which cell the point is found in. This + * does not matter (to within the same tolerance) if the finite element + * field is continuous. On the other hand, if the finite element in use + * is not continuous, then you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template void @@ -2122,6 +2177,17 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the value of the finite element field either + * here or there, depending on which cell the point is found in. This + * does not matter (to within the same tolerance) if the finite element + * field is continuous. On the other hand, if the finite element in use + * is not continuous, then you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template void @@ -2141,6 +2207,17 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the value of the finite element field either + * here or there, depending on which cell the point is found in. This + * does not matter (to within the same tolerance) if the finite element + * field is continuous. On the other hand, if the finite element in use + * is not continuous, then you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template typename VectorType::value_type @@ -2154,6 +2231,17 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the value of the finite element field either + * here or there, depending on which cell the point is found in. This + * does not matter (to within the same tolerance) if the finite element + * field is continuous. On the other hand, if the finite element in use + * is not continuous, then you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template typename VectorType::value_type @@ -2172,6 +2260,16 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the gradient of the finite element field either + * here or there, depending on which cell the point is found in. Since + * the gradient is, for most elements, discontinuous from one cell or + * the other, you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template void @@ -2185,6 +2283,16 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the gradient of the finite element field either + * here or there, depending on which cell the point is found in. Since + * the gradient is, for most elements, discontinuous from one cell or + * the other, you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template void @@ -2203,6 +2311,16 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the gradient of the finite element field either + * here or there, depending on which cell the point is found in. Since + * the gradient is, for most elements, discontinuous from one cell or + * the other, you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template Tensor<1, spacedim, typename VectorType::value_type> @@ -2215,6 +2333,16 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the gradient of the finite element field either + * here or there, depending on which cell the point is found in. Since + * the gradient is, for most elements, discontinuous from one cell or + * the other, you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template Tensor<1, spacedim, typename VectorType::value_type> @@ -2232,6 +2360,16 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the gradient of the finite element field either + * here or there, depending on which cell the point is found in. Since + * the gradient is, for most elements, discontinuous from one cell or + * the other, you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template void @@ -2246,6 +2384,16 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the gradient of the finite element field either + * here or there, depending on which cell the point is found in. Since + * the gradient is, for most elements, discontinuous from one cell or + * the other, you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template void @@ -2265,6 +2413,16 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the gradient of the finite element field either + * here or there, depending on which cell the point is found in. Since + * the gradient is, for most elements, discontinuous from one cell or + * the other, you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template Tensor<1, spacedim, typename VectorType::value_type> @@ -2278,6 +2436,16 @@ namespace VectorTools * * @note If the cell in which the point is found is not locally owned, an * exception of type VectorTools::ExcPointNotAvailableHere is thrown. + * + * @note This function needs to find the cell within which a point lies, + * and this can only be done up to a certain numerical tolerance of course. + * Consequently, for points that are on, or close to, the boundary of + * a cell, you may get the gradient of the finite element field either + * here or there, depending on which cell the point is found in. Since + * the gradient is, for most elements, discontinuous from one cell or + * the other, you will get unpredictable values for + * points on or close to the boundary of the cell, as one would expect + * when trying to evaluate point values of discontinuous functions. */ template Tensor<1, spacedim, typename VectorType::value_type>