# [R-es] Convertir programa Matlab a R sacado de Threshold Models of Collective Behavior de Michèle Lai & Yann Poltera

Sebastian Kruk residuo.solow en gmail.com
Mar Ene 24 14:18:35 CET 2017

```Estimados Usuarios-R:

Estoy convirtiendo un programa en Matlab a R.

El original lo saqué de:

Lai, M., & Poltera, Y. (2009). Lecture with computer exercises: Modelling and simulating social systems with matlab. Tech. rep., Swiss Federal Institute of Technology (December 2009). 27.

Ahora estoy convirtiendo la siguiente función:

function sizes = gridsizes(N,varargin)
% gridsizes(N) calculates the best factorization of N into two integers N1 and
% N2 such that : N1xN2 == N and N2-N1 -> min (optimal grid)
% gridsizes(N,C1,C2) calculates the best factorization of N into two integers N1 and
% N2 such that : N1xN2 == N and N2-N1 -> min, under the condition that N1
% divides C1 and N2 divides C2 (optimal subgrids for an already existing
% grid of size C1xC2  N)
% gridsizes(N,C1,C2,1) returns [NaN;NaN] instead of an error message if the
% fitting couldn't be found (used in the function N_from_d)
sizes = NaN(2,1);
s = sqrt(N);
tol = 10ˆ(-12);
N2= ceil(s);
N1 = N/N2;
if(nargin  3)
C1 = varargin{1};
C2 = varargin{2};
while(rem(C1,N1) > tol || rem(C2,N2) > tol || rem(N1,round(N1)) > tol)
N2 = N2+1;
N1 = N/N2;
if(N2 > N)
if(nargin  4 && varargin{3} == 1)
45
N1 = NaN;
N2 = NaN;
break;
else
error('Cannot find subgrid fitting to the given grid');
end
end
end
else
while(rem(N1,round(N1)) > tol)
N2 = N2+1;
N1 = N/N2;
end
end
sizes(1) = N1;
sizes(2) = N2;
end

En R me quedó así:

gridsizes <- function(N,...) {
sizes <- matrix(NA,2,1)
s = sqrt(N)
tol = 10^(-12)
N2 = ceiling(s)
N1 = N/N2
a = list(...)
if(length(a)>=3) {
C1 = a[[1]]
C2 = a[[2]]
while((C1%%N1) > tol || (C2%%N2) > tol || (N1 %% round(N1)) > tol) {
N2 = N2+1
N1 = N/N2
if(N2 > N) {
if(length(a) >= 4 && a[[3]] == 1) {
N1 = NA
N2 = NA
}
else {
print("ERROR: no se puede hallar una subgrilla que entre en la grilla dada")
}
}
}
}
else {
while((N1%%round(N1)) > tol) {
N2 = N2+1
N1 = N/N2
}
}
sizes[1] = N1
sizes[2] = N2
}

En alguna parte se tranca y no sale del bucle pues si lo cancelo me aparece el error [1] "ERROR: no se puede hallar una subgrilla que entre en la grilla dada" repetido en forma indefinida.

No me doy cuenta doy estoy errando.

¿Alguien se da cuenta?

Saludos,

Sebastián.

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