I have very long expressions stored in a .txt file. By copying this epxression into R, it is represented in one line. When I try to run it, it doesn't work and errors like "unexpected symbol" or "unexpected numeric constant" appear. However, if I insert line breaks at arbitrary places, e.g. after every 3000 characters, it works smoothly.
Does anyone know how to handle this problem? In particular, is it possible to make these line breaks automatically or are there other possible solutions?
alpha <- 0.025; d1 <- 0.027; d2 <- 0.037; mu1 <- 0.024; mu2 <- 0.026; Z1 <- 0.6; Z2 <- 0.7; rho11 <- 0.076;
rho12 <- 0.074; rho21 <- 0.073; rho22 <- 0.072; S11 <- 0.086; S12 <- 0.087; S21 <- 0.084; S22 <- 0.083; u <- 2
exp(mu1*(mu1*u*d1^2 + d2*mu2*u*d1) - log(1 - 2*S22*d2^2*u - 2*S12*d1*d2*u - 2*S21*d1*d2*u - 2*S11*d1^2*u)/2 + mu2*(mu2*u*d2^2 + d1*mu1*u*d2) - (S21*((2*(S12*u*d2^2 + S11*d1*u*d2)*(d1^2*mu1*u + alpha*d1*u + d1*d2*mu2*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((d2^2*mu2*u + alpha*d2*u + d1*d2*mu1*u)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((2*(S21*u*d1^2 + S22*d2*u*d1)*(d2^2*mu2*u + alpha*d2*u + d1*d2*mu1*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((d1^2*mu1*u + alpha*d1*u + d1*d2*mu2*u)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))*(2*d1^2*mu1*u + 2*alpha*d1*u + 2*d1*d2*mu2*u) - (S22*((2*(S12*u*d2^2 + S11*d1*u*d2)*(d1^2*mu1*u + alpha*d1*u + d1*d2*mu2*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((d2^2*mu2*u + alpha*d2*u + d1*d2*mu1*u)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((2*(S21*u*d1^2 + S22*d2*u*d1)*(d2^2*mu2*u + alpha*d2*u + d1*d2*mu1*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((d1^2*mu1*u + alpha*d1*u + d1*d2*mu2*u)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))*(2*d2^2*mu2*u + 2*alpha*d2*u + 2*d1*d2*mu1*u) + Z1*(rho11*(2*d1^2*mu1*u + 2*alpha*d1*u + 2*d1*d2*mu2*u) - rho21*(d2^2*u*(S22*((2*(S12*u*d2^2 + S11*d1*u*d2)*(4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((2*(S21*u*d1^2 + S22*d2*u*d1)*(4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1))) + d1*d2*u*(S21*((2*(S12*u*d2^2 + S11*d1*u*d2)*(4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((2*(S21*u*d1^2 + S22*d2*u*d1)*(4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))) - rho11*(d1^2*u*(S21*((2*(S12*u*d2^2 + S11*d1*u*d2)*(4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((2*(S21*u*d1^2 + S22*d2*u*d1)*(4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1))) + d1*d2*u*(S22*((2*(S12*u*d2^2 + S11*d1*u*d2)*(4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((2*(S21*u*d1^2 + S22*d2*u*d1)*(4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))) + rho21*(2*d2^2*mu2*u + 2*alpha*d2*u + 2*d1*d2*mu1*u) + 2*alpha*d1*u) + Z2*(rho12*(2*d1^2*mu1*u + 2*alpha*d1*u + 2*d1*d2*mu2*u) - rho22*(d2^2*u*(S22*((2*(S12*u*d2^2 + S11*d1*u*d2)*(4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((2*(S21*u*d1^2 + S22*d2*u*d1)*(4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1))) + d1*d2*u*(S21*((2*(S12*u*d2^2 + S11*d1*u*d2)*(4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((2*(S21*u*d1^2 + S22*d2*u*d1)*(4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))) - rho12*(d1^2*u*(S21*((2*(S12*u*d2^2 + S11*d1*u*d2)*(4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((2*(S21*u*d1^2 + S22*d2*u*d1)*(4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1))) + d1*d2*u*(S22*((2*(S12*u*d2^2 + S11*d1*u*d2)*(4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((2*(S21*u*d1^2 + S22*d2*u*d1)*(4*d2^2*mu2*u + 4*alpha*d2*u + 4*d1*d2*mu1*u))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - ((4*d1^2*mu1*u + 4*alpha*d1*u + 4*d1*d2*mu2*u)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))) + rho22*(2*d2^2*mu2*u + 2*alpha*d2*u + 2*d1*d2*mu1*u) + 2*alpha*d2*u) + 2*alpha^2*u + Z1*(Z1*(rho11*(rho11*u*d1^2 + d2*rho21*u*d1) + rho21*(rho21*u*d2^2 + d1*rho11*u*d2) - rho11*(d1^2*u*(S21*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho11*u*d1^2 + d2*rho21*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho21*u*d2^2 + d1*rho11*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho21*u*d2^2 + d1*rho11*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho11*u*d1^2 + d2*rho21*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1))) + d1*d2*u*(S22*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho11*u*d1^2 + d2*rho21*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho21*u*d2^2 + d1*rho11*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho21*u*d2^2 + d1*rho11*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho11*u*d1^2 + d2*rho21*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))) - rho21*(d2^2*u*(S22*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho11*u*d1^2 + d2*rho21*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho21*u*d2^2 + d1*rho11*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho21*u*d2^2 + d1*rho11*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho11*u*d1^2 + d2*rho21*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1))) + d1*d2*u*(S21*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho11*u*d1^2 + d2*rho21*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho21*u*d2^2 + d1*rho11*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho21*u*d2^2 + d1*rho11*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho11*u*d1^2 + d2*rho21*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))) + d1^2*u) + Z2*(rho11*(rho12*u*d1^2 + d2*rho22*u*d1) + rho21*(rho22*u*d2^2 + d1*rho12*u*d2) - rho11*(d1^2*u*(S21*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho12*u*d1^2 + d2*rho22*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho22*u*d2^2 + d1*rho12*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho22*u*d2^2 + d1*rho12*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho12*u*d1^2 + d2*rho22*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1))) + d1*d2*u*(S22*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho12*u*d1^2 + d2*rho22*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho22*u*d2^2 + d1*rho12*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho22*u*d2^2 + d1*rho12*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho12*u*d1^2 + d2*rho22*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))) - rho21*(d2^2*u*(S22*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho12*u*d1^2 + d2*rho22*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho22*u*d2^2 + d1*rho12*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho22*u*d2^2 + d1*rho12*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho12*u*d1^2 + d2*rho22*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1))) + d1*d2*u*(S21*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho12*u*d1^2 + d2*rho22*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho22*u*d2^2 + d1*rho12*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho22*u*d2^2 + d1*rho12*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho12*u*d1^2 + d2*rho22*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))) + d1*d2*u)) + Z2*(Z2*(rho12*(rho12*u*d1^2 + d2*rho22*u*d1) + rho22*(rho22*u*d2^2 + d1*rho12*u*d2) - rho12*(d1^2*u*(S21*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho12*u*d1^2 + d2*rho22*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho22*u*d2^2 + d1*rho12*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho22*u*d2^2 + d1*rho12*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho12*u*d1^2 + d2*rho22*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1))) + d1*d2*u*(S22*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho12*u*d1^2 + d2*rho22*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho22*u*d2^2 + d1*rho12*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho22*u*d2^2 + d1*rho12*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho12*u*d1^2 + d2*rho22*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))) - rho22*(d2^2*u*(S22*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho12*u*d1^2 + d2*rho22*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho22*u*d2^2 + d1*rho12*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho22*u*d2^2 + d1*rho12*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho12*u*d1^2 + d2*rho22*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1))) + d1*d2*u*(S21*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho12*u*d1^2 + d2*rho22*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho22*u*d2^2 + d1*rho12*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho22*u*d2^2 + d1*rho12*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho12*u*d1^2 + d2*rho22*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))) + d2^2*u) + Z1*(rho12*(rho11*u*d1^2 + d2*rho21*u*d1) + rho22*(rho21*u*d2^2 + d1*rho11*u*d2) - rho12*(d1^2*u*(S21*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho11*u*d1^2 + d2*rho21*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho21*u*d2^2 + d1*rho11*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho21*u*d2^2 + d1*rho11*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho11*u*d1^2 + d2*rho21*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1))) + d1*d2*u*(S22*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho11*u*d1^2 + d2*rho21*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho21*u*d2^2 + d1*rho11*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho21*u*d2^2 + d1*rho11*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho11*u*d1^2 + d2*rho21*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))) - rho22*(d2^2*u*(S22*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho11*u*d1^2 + d2*rho21*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho21*u*d2^2 + d1*rho11*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S12*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho21*u*d2^2 + d1*rho11*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho11*u*d1^2 + d2*rho21*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1))) + d1*d2*u*(S21*((4*(S12*u*d2^2 + S11*d1*u*d2)*(rho11*u*d1^2 + d2*rho21*u*d1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho21*u*d2^2 + d1*rho11*u*d2)*(2*S11*u*d1^2 + 2*S12*d2*u*d1 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)) + S11*((4*(S21*u*d1^2 + S22*d2*u*d1)*(rho21*u*d2^2 + d1*rho11*u*d2))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1) - (2*(rho11*u*d1^2 + d2*rho21*u*d1)*(2*S22*u*d2^2 + 2*S21*d1*u*d2 - 1))/(2*S11*d1^2*u + 2*S22*d2^2*u + 2*S12*d1*d2*u + 2*S21*d1*d2*u - 1)))) + d1*d2*u)) + 2*alpha*d1*mu1*u + 2*alpha*d2*mu2*u)
The cause of this is described well in the answer to this question
In your case, since you've got the expression in a file, you can source() the file from R, rather than copying and pasting. Either you need to add an assignment in your text file, or you can do:
source("filename.txt")$value
to get the result of the computation
You mention in the comments that you want to be able to use this in an optimisation - a simple example over one dimension to find an alpha that minimise the expression would be:
f <- function(alpha){source("o:\\test.txt")$value}
optim(1, f, lower=0.5, upper=1.5, method="L-BFGS-B")
#$par
#[1] 1
#
#$value
#[1] 1.011915
#
#$counts
#function gradient
# 1 1
#
#$convergence
#[1] 0
#
#$message
#[1] "CONVERGENCE: NORM OF PROJECTED GRADIENT <= PGTOL"