📄 simple_lookup.adb
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---------------------------------------------------------------------------------- ---- File : simple_lookup.adb $Revision: 1.6 $ ---- Abstract: ---- Body of the Ada S-Function simple_lookup. This example S-Function ---- illustrates the idea of writing a "wrapper" S-Function that "wraps" ---- standalone Ada code (i.e., ada packages and procedures) both for ---- use with Simulink as an S-Function, and directly with Ada code ---- generated using the RTW Ada Coder. ---- ---- For the purpose of illustration, a simple lookup table example is ---- implemented here as an S-Function. This S-Function takes three ---- parameters: ---- Parameter 1: "Xvalues", which must be a monotonically increasing ---- double vector with atleast two elements: ---- ---- -inf < X1 < X2 < ... < Xn < inf ---- ---- Parameter 2: "Yvalues", which must be a double vector and it should ---- have one element more than the Xvalues vector: ---- ---- Y0, Y1, Y2, ..., Yn ---- ---- Parameter 3: "LookupMethod", which must be one of the two strings, ---- either "left" or "right". This specifies which lookup ---- method to use. ---- ---- The two simple algoithms implemented in the package lookup_methods ---- allow us to make this S-function have the following functionality: ---- ---- If Lookup Method == "left" then: ---- ---- inp <= X1 => out1 = y0 ---- X1 < inp <= X2 => out1 = y1 ---- X2 < inp <= X3 => out1 = y2 ---- : ---- : ---- Xn-1 < inp <= Xn => out1 = yn-1 ---- Xn < inp => out1 = yn ---- ---- If Lookup Method == "right" then: ---- ---- inp < X1 => out1 = y0 ---- X1 <= inp < X2 => out1 = y1 ---- X2 <= inp < X3 => out1 = y2 ---- : ---- : ---- Xn-1 <= inp < Xn => out1 = yn-1 ---- Xn <= inp => out1 = yn ---- ---- ---- The second output port is used as an intermediate storage area by the ---- lookup algorithm to remember the last index into the table, this index ---- is used as a starting point for the search to bracket the input. ---- ---- The lookup algorithms used in this S-Function are not used or related ---- to the actual lookup table blocks that you see in the Simulink block ---- library. This S-Funciton and the supporting lookup_methods package is ---- merely used to illustrate the functionality of Ada S-Functions. ---- ---- Author : Murali Yeddanapudi and Tom Weis, 26-Jul-1999 ---- ---- Copyright 1990-2002 The MathWorks, Inc.-- ----------------------------------------------------------------------------------with Lookup_Methods;with Simulink; use Simulink;with Ada.Exceptions; use Ada.Exceptions;package body Simple_Lookup is X_VALUES_PRM_IDX : constant integer := 0; Y_VALUES_PRM_IDX : constant integer := 1; LOOKUP_MTH_PRM_IDX : constant integer := 2; NUM_PARAMS_EXPECTED : constant integer := 3; -- Procedure: IsLookupValuesParameterValid ---------------------------------- -- Abstract:: -- Utility subrutine to check if the x and y table data parameters are -- valid. -- function IsLookupValuesParameterValid (S : in SimStruct; PrmIdx : in Integer) return Boolean is NumDims : Integer := ssGetParameterNumDimensions(S, PrmIdx); Dims : array(0 .. NumDims-1) of Integer; for Dims'Address use ssGetParameterDimensions(S, PrmIdx); Width : Integer := SsGetParameterWidth(S, PrmIdx); begin if ( not(ssGetParameterIsDouble(S, PrmIdx)) or (NumDims /= 2) or (Dims(0) /= 1 and Dims(1) /= 1) or (Width < 2) ) then return(FALSE); else return(TRUE); end if; end IsLookupValuesParameterValid; ------------------------------------------- -- Procedure: mdlCheckParameters -------------------------------------------- -- Abstract:: -- Verify that the parameter passed to the S-Function via its dialog -- box are okay. -- procedure mdlCheckParameters(S : in SimStruct) is NumActParams : Integer := ssGetNumParameters(S); begin -- Expected number of parameters if (NumActParams /= NUM_PARAMS_EXPECTED) then ssSetErrorStatus(S, "Parameter count mismatch. Expecting " & Integer'Image(NUM_PARAMS_EXPECTED) & " parameter " & "while " & Integer'Image(NumActParams) & " were " & "provided in the block dialog box"); return; end if; -- X values parameter must be a double vector with atleast two elements. if not(IsLookupValuesParameterValid(S, X_VALUES_PRM_IDX)) then ssSetErrorStatus(S, "The X data parameter mustbe a double " & "vector with atleast two elements"); return; end if; -- Y values parameter must be a double vector with atleast two elements. if not(IsLookupValuesParameterValid(S, Y_VALUES_PRM_IDX)) then ssSetErrorStatus(S, "The Y data parameter must be a double " & "vector with atleast two elements"); return; end if; -- Lookup method must be string that is either "left" or "right" declare ErrMsg : String := "The " & Integer'Image(LOOKUP_MTH_PRM_IDX+1) & "rd parameter must be a string, either 'left' or 'right', that " & "specifies the lookup method"; begin if ssGetParameterIsChar(S, LOOKUP_MTH_PRM_IDX) then declare LookupMth : String := ssGetStringParameter(S,LOOKUP_MTH_PRM_IDX); begin if (LookupMth /= "left" and LookupMth /= "right") then ssSetErrorStatus(S, ErrMsg); end if; end; else ssSetErrorStatus(S, ErrMsg); return; end if; end; declare XLen : Integer := ssGetParameterWidth(S, X_VALUES_PRM_IDX); XValues : array(1 .. XLen) of Real_T; for XValues'Address use ssGetParameterAddress(S, X_VALUES_PRM_IDX); YLen : Integer := ssGetParameterWidth(S, Y_VALUES_PRM_IDX); begin -- Y values vector must be one longer than the X values vector if ( XLen+1 /= YLen ) then ssSetErrorStatus(S, "The Y values vector length (" & Integer'Image(YLen) & ") must be one greater " & "than the x values parameter vector length (" & Integer'Image(XLen) & ")"); return; end if; -- X values vector must be monotonically increasing for I in 1 .. XLen-1 loop if ( XValues(I) > XValues(I+1) ) then ssSetErrorStatus(S, "X values parameter values must " & "be monotonically increasing");⌨️ 快捷键说明
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