#This is a function for resource dynamics of nospec species and one resource
res1_plot_para = function(specpara,supply,loss,paratochange,inival,endval,stepval) {
# species parameters:
# 1 growth: growth per unit biomass (u)
# 2 uptake: uptake per unit growth (w)
# 3 mortality (d)
# 4 initial size (n0)

#resource parameters:
# 5          supply: resource supply (S)
# 6          loss: rate at which resource is removed (a)

#further parameters:
# paratochange: number of the para to be changed (see above)
# inival: initial parameter value
# endval: final parameter value
# stepval: parameter change step
# animation - whether to animate

#paratochange = fix(paratochange);

  if (paratochange < 1 | paratochange > 6 | paratochange == 4) {
    print('Bad parameter code')
    return()
  }

  paraname = c('Growth','Uptake','Mortality','         ','Supply','Loss')
  para=NULL
  para[1] = specpara[1]; 
  para[2] = specpara[2]; 
  para[3] = specpara[3]; 
  para[5] = supply;
  para[6] = loss;

  para[paratochange] = inival;
  Nstarini = (para[5]- para[6]*para[3]/para[1]) / (para[2] * para[3]);
  Rstarini = para[3]/para[1];
  Rfreeini = para[5]/para[6];
  para[paratochange] = endval;
  Nstarend = (para[5]- para[6]*para[3]/para[1]) / (para[2] * para[3]);
  Rstarend = para[3]/para[1];
  Rfreeend = para[5]/para[6];

  maxx = 1.2*max(c(Rstarini, Rstarend, Rfreeini, Rfreeend));
  maxy = 1.2*max(c(50, Nstarini, Nstarend));
  nobin = 100;
   
  for (value in seq( inival,endval, by=stepval)) {
    para[paratochange] = value;
    Nstar = (para[5]- para[6]*para[3]/para[1]) / (para[2] * para[3]);
    Rstar = para[3]/para[1];
    Rfree = para[5]/para[6];
    #text = sprintf('#s #7.2g  Rfree #7.2f  Rstar #7.2f   Nstar  #7.2f', paraname(:,paratochange), value, Rfree,Rstar,Nstar);

 
    xhyp=NULL;
    yhyp=NULL;
    count=1
    for (t1 in seq(para[5]/(para[6]*nobin),para[5]/para[6],by=para[5]/(para[6]*nobin))) {
      xhyp[count] = t1
      yhyp[count] = (para[5]- para[6]*t1)/(para[2]*para[1]*t1)
      count = count + 1
    }
    titl = paste(paraname[paratochange],": ",value,"Rstar: ",format(Rstar,digits=4), "Nstar: ", format(Nstar,digits=4))
    plot(xhyp,yhyp,type="l",col="blue",xlim=c(0,maxx),ylim=c(0,maxy),xlab='Resource', ylab='Species',lwd=2,main=titl);
    lines(c(Rstar, Rstar),c(0, maxy),col="green",lwd=2);
    if (Rstar>0)
      points(Rstar,Nstar,col='red',pch=19);
   
    Sys.sleep(2)
  }
}