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Interval package: Difference between revisions
→Reverse arithmetic operations
m (After implementation of the general interval power function it is possible to compute powers with an operator) |
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=== Reverse arithmetic operations === | === Reverse arithmetic operations === | ||
[[File:Reverse-power-functions.png|400px|thumb|right|Reverse power operations. The relevant subset of the function's domain, where ''x''<sup>''y''</sup> ∈ [2, 3], is outlined and hatched.]] | |||
Some arithmetic functions also provide reverse mode operations. That is inverse functions with interval constraints. For example the <code>sqrrev</code> can compute the inverse of the <code>sqr</code> function on intervals. | Some arithmetic functions also provide reverse mode operations. That is inverse functions with interval constraints. For example the <code>sqrrev</code> can compute the inverse of the <code>sqr</code> function on intervals. | ||
In the following example, we compute the constraints for base and exponent of the power function <code>pow</code> as shown in the figure. | |||
octave:1> x = powrev1 (infsup ("[1.1, 1.45]"), infsup (2, 3)) | |||
x = [1.6128979635153644, 2.7148547265657923] | |||
octave:2> y = powrev2 (infsup ("[2.14, 2.5]"), infsup (2, 3)) | |||
y = [.7564707973660299, 1.4440113978403289] | |||
=== Numerical operations === | === Numerical operations === | ||