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NumericalDerivativesGetStats Method
Returns status information. This information might prove useful to the user wanting to gain better control over the differencing parameters. This information can often be ignored.

Namespace: Imsl.Math
Assembly: ImslCS (in ImslCS.dll) Version: 6.5.2.0
Syntax
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public int[] GetStats()

Return Value

Type: Int32
An int array containing the ten diagnostic values described in the following table. These values can be used to monitor the progress or expense of the Jacobian computation.
indexDescription
0the number of times a function evaluation was computed.
1the number of columns in which three attempts were made to increase a percentage factor for differencing (i.e. a component in the factor array) but the computed del remained unacceptably small relative to y[j-1] or scale[j-1]. In such cases the percentage factor is set to 1.4901161193847656e-8, which is the square root of machine precision
2the number of columns in which the computed del was zero to machine precision because y[j-1] or scale[j-1] was zero. In such cases del is set to 1.4901161193847656e-8, which is the square root of machine precision
3the number of Jacobian columns which had to be recomputed because the largest difference formed in the column was close to zero relative to scale, where
scale = \max \left( {\left| {f_i \left( y \right)} \right|,\left| {f_i (y + del \times e_{j} )} \right|} \right)
and i denotes the row index of the largest difference in the column currently being processed. index = 9 gives the last column where this occurred.
4the number of columns whose largest difference is close to zero relative to scale after the column has been recomputed.
5the number of times scale information was not available for use in the roundoff and truncation error tests. This occurs when
\min \left( {\left| {f_i \left( y \right)} \right|,\left| {f_i (y + del \times e_{j} )} \right|} \right) = 0
where i is the index of the largest difference for the column currently being processed.
6the number of times the increment for differencing (del) was computed and had to be increased because (scale[j-1]+del) - scale[j-1]) was too small relative to y[j-1] or scale[j-1].
7the number of times a component of the factor array was reduced because changes in function values were large and excess truncation error was suspected. index = 8 gives the last column in which this occurred.
8the index of the last column where the corresponding component of the factor array had to be reduced because excessive truncation error was suspected.
9the index of the last column where the difference was small and the column had to be recomputed with an adjusted increment (see index = 3). The largest derivative in this column may be inaccurate due to excessive roundoff error.
See Also