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.MathAssembly: ImslCS (in ImslCS.dll) Version: 6.5.2.0
Syntax Public Function GetStats As Integer()
public:
array<int>^ GetStats()
member GetStats : unit -> int[]
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.
index | Description |
---|
0 | the number of times a function evaluation was
computed. |
1 | the 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 |
2 | the 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 |
3 | the 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
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. |
4 | the number of columns whose largest difference is
close to zero relative to scale after the column has been
recomputed. |
5 | the number of times scale information was not
available for use in the roundoff and truncation error tests. This
occurs when
where i is the index of the largest difference for the column
currently being processed. |
6 | the 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]. |
7 | the 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. |
8 | the index of the last column where the
corresponding component of the factor array had to be
reduced because excessive truncation error was suspected. |
9 | the 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