Characteristic Maps (C Code)

Characteristic maps defined in the component are evaluated via three subroutines each (as in ESDL).

Table LLpr2 from Linear Interpolation (2D) is again used as an example for a characteristic map:

y \ x	0.0	1.0	8.0	15.0
1.0	-5.0	-3.0	0.0	1.0
3.0	0.0	1.0	4.0	6.0
5.0	8.0	5.0	4.0	4.0

The CharTable2_search_real64_real64(charline,indx, indY)subroutine is usually sufficient for the evaluation of characteristic lines. Linear interpolation for this example works as follows:

EXAMPLE

tmpVal = CharTable2_getAt_real64_real64_real64(LLpr2,8,5)
// assigns 4.0 to tmpVal

tmpVal = CharTable2_getAt_real64_real64_real64(LLpr2,2,2);
// calculates interpol. factor for x=2 and y=2
// interpolates value for (2,2) as -0.571 and
// assigns it to tmpVal

tmpVal = CharTable2_getAt_real64_real64_real64(LLpr2,20,9);
// calculates extrapol. factor for x=20, y=10
// extrapolates value for (20,10) as 5.0 and
// assigns it to tmpVal

In some special cases, though, separating the search and interpolate steps in tables can be more efficient. In these cases, the subroutines CharTable2_search_real64_real64(charmap,indX, indY) and CharTable2_interpol_real64_real64_real64(charmap) are used.

EXAMPLE

CharTable2_search_real64_real64(LLpr2, 1, 3);
// sets x sample point to 1
// and y sample point to 3

tmpVal = CharTable2_interpol_real64_real64_real64(LLpr2);
// assigns 1.0 to tmpVal

CharTable2_search_real64_real64(LLpr2,4,4);
// calculates interpol. factor for x=4, y=4

tmpVal = CharTable2_interpol_real64_real64_real64(LLpr2);
// interpolates value for (4,4) as 3.143 and
// assigns it to tmpVal

In addition to the interpolation routines provided by ASCET, you can add user-defined interpolation routines, or you can mark interpolation routines as high-resolution.

Note
The interpolation routines provided with ASCET are examples, not intended to be used in production or in ECUs running in a vehicle. See also the ASCET‑SE user guide.