How to simplify too much of if

I assume that my code below could be simplified to something more shorter but i cant think of how.

if (0<S)&&(S<=10)
    if AggS==10
        if fap==40
            if fwcr==0.5
                fp=39;
            else
                fp=45;
            end
        elseif fap==60
             if fwcr==0.5
                fp=33;
            else
                fp=36   ;
             end
        elseif fap==80
             if fwcr==0.5
                fp=27;
            else
                fp=30;
             end
        end
    else
        if fap==40
            if fwcr==0.5
                fp=29;
            else
                fp=33;
            end
        elseif fap==60
             if fwcr==0.5
                fp=24;
            else
                fp=28;
             end
        elseif fap==80
             if fwcr==0.5
                fp=20;
            else
                fp=24;
             end
        end
    end
elseif (10<S)&&(S<=30)
   if AggS==10
        if fap==40
            if fwcr==0.5
                fp=41;
            else
                fp=46;
            end
        elseif fap==60
             if fwcr==0.5
                fp=34;
            else
                fp=38;
             end
        elseif fap==80
             if fwcr==0.5
                fp=29;
            else
                fp=32;
             end
        end
    else
        if fap==40
            if fwcr==0.5
                fp=32;
            else
                fp=36;
            end
        elseif fap==60
             if fwcr==0.5
                fp=25;
            else
                fp=30;
             end
        elseif fap==80
             if fwcr==0.5
                fp=22;
            else
                fp=25;
             end
        end
    end
elseif (30<S)&&(S<=60)
    if AggS==10
        if fap==40
            if fwcr==0.5
                fp=36;
            else
                fp=49;
            end
        elseif fap==60
             if fwcr==0.5
                fp=38;
            else
                fp=41;
             end
        elseif fap==80
             if fwcr==0.5
                fp=31;
            else
                fp=34;
             end
        end
    else
        if fap==40
            if fwcr==0.5
                fp=35;
            else
                fp=39;
            end
        elseif fap==60
             if fwcr==0.5
                fp=29;
            else
                fp=32;
             end
        elseif fap==80
             if fwcr==0.5
                fp=24;
            else
                fp=37;
             end
        end
    end
elseif (60<S)&&(S<=180)
    if AggS==10
        if fap==40
            if fwcr==0.5
                fp=50;
            else
                fp=55;
            end
        elseif fap==60
             if fwcr==0.5
                fp=42;
            else
                fp=45;
             end
        elseif fap==80
             if fwcr==0.5
                fp=35;
            else
                fp=37;
             end
        end
    else
        if fap==40
            if fwcr==0.5
                fp=41;
            else
                fp=44;
            end
        elseif fap==60
             if fwcr==0.5
                fp=32;
            else
                fp=36;
             end
        elseif fap==80
             if fwcr==0.5
                fp=27;
            else
                fp=31;
             end
        end
    end
end

[Sulaymon Eshkabilov]

Maybe you can try

switch .. case

Answer 1

[Walter Roberson]

Use look-up tables. For example the final elseif can be encoded as

{[40 50 55
 60 42 45
 80 35 37]
[40 41 44
 60 32 36
 80 27 31]}

with the logic that you index the cell by {2 - (AggS==10)} and then you ismember(fap, CellContents(:,1)) to figure out which row you are talking about, and you pull out column 2 if fwcr==0.5 and column 3 otherwise.

You can use discretize to figure out which S case you are working with so pretty much everything can go into the same data structure.

Answer 2

[Jan]

Change:

if (0<S)&&(S<=10)
    if AggS==10
        if fap==40
            if fwcr==0.5
                fp=39;
            else
                fp=45;
            end
        elseif fap==60
             if fwcr==0.5
                fp=33;
            else
                fp=36   ;
             end
        elseif fap==80
             if fwcr==0.5
                fp=27;
            else
                fp=30;
             end
        end
    else
        if fap==40
            if fwcr==0.5
                fp=29;
            else
                fp=33;
            end
        elseif fap==60
             if fwcr==0.5
                fp=24;
            else
                fp=28;
             end
        elseif fap==80
             if fwcr==0.5
                fp=20;
            else
                fp=24;
             end
        end
    end
    ...        

to:

if (0<S) && (S<=10)
   if AggS == 10
      switch fap
         case 40
            v = [45, 39];
         case 60
            v = [36, 33];
         case 80
            v = [30, 27];
      end
   else
      switch fap
         case 40
            v = [33, 29];
         case 60
            v = [28, 24];
         case 80
            v = [24, 20];
      end
   end
...
end
fp = v((fwcr == 0.5) + 1);

A next step:

if (0<S) && (S<=10)
   if AggS == 10
      v = [45, 39; 36, 33; 30, 27];
   else
      v = [33, 29; 28, 24; 24, 20];
   end
...
end
i1 = (fap == [40, 60, 80]);
i2 = (fwcr == 0.5) + 1;
fp = v(i1, i2);

Indexing in arrays is more compact than a pile of if conditions.

Answer 3

[Matt J]

FP=[39 45 33 36 27 30, 29,33,24,28,20,24,...
    41 46 34,38,29,32,32,36,25,30,22,25,36,49,38,41,31,34,35,39,....
    29,32,24,37,50,55,42,45,35,37,41,44,32,36,27,31];

FP=reshape(FP,2,3,2,4);

G=griddedInterpolant({1:2, [40,60,80],1:2,1:4},FP);

fap=40;AggS=10;fwcr=0.5; S=30;  %hypothetical input

fp=G(2-(fwcr==0.5),fap,2-(AggS==10),...
    discretize(S,[0,10,30,60,180],'IncludedEdge', 'right'))

fp = 41