--- /dev/null	Thu Jan 01 00:00:00 1970 +0000
+++ b/marea_2/utils/CBS_backend.py	Mon Jul 22 11:24:27 2024 +0000
@@ -0,0 +1,200 @@
+from swiglpk import *
+import random
+import pandas as pd
+import numpy as np
+import cobra as cb
+
+# Initialize LP problem
+def initialize_lp_problem(S):
+
+    len_vector=len(S.keys())
+    values=list(S.values())
+    indexes=list(S.keys())
+    ia = intArray(len_vector+1); 
+    ja = intArray(len_vector+1);
+    ar = doubleArray(len_vector+1);
+    
+    i=0
+    ind_row=[indexes[i][0]+1 for i in range(0, len(values) )]
+    ind_col=[indexes[i][1]+1 for i in range(0, len(values) )]
+    for i in range(1, len(values) + 1): 
+        ia[i]=ind_row[i-1]
+        ja[i]=ind_col[i-1]
+        ar[i] = values[i-1]
+    
+    nrows=S.shape[0]
+    ncol=S.shape[1]
+    
+    return len_vector, values, indexes, ia, ja, ar, nrows, ncol
+    
+    
+
+# Solve LP problem from the structure of the metabolic model
+def create_and_solve_lp_problem(lb,ub,nrows, ncol, len_vector, ia, ja, ar, 
+                                obj_coefs,reactions,return_lp=False):
+    
+    
+    lp = glp_create_prob();
+    glp_set_prob_name(lp, "sample");
+    glp_set_obj_dir(lp, GLP_MAX);
+    glp_add_rows(lp, nrows);
+    eps = 1e-16
+    for i in range(nrows):
+        glp_set_row_name(lp, i+1, "constrain_"+str(i+1));
+        glp_set_row_bnds(lp, i+1, GLP_FX, 0.0, 0.0);
+    glp_add_cols(lp, ncol);
+    for i in range(ncol):
+        glp_set_col_name(lp, i+1, "flux_"+str(i+1));
+        glp_set_col_bnds(lp, i+1, GLP_DB,lb[i]-eps,ub[i]+eps);
+    glp_load_matrix(lp, len_vector, ia, ja, ar);
+    
+    try:
+        fluxes,Z=solve_lp_problem(lp,obj_coefs,reactions)
+        if return_lp:
+            return fluxes,Z,lp
+        else:
+            glp_delete_prob(lp);
+            return fluxes,Z
+    except Exception as e:
+        glp_delete_prob(lp)
+        raise Exception(e)
+    
+    
+# Solve LP problem from the structure of the metabolic model
+def solve_lp_problem(lp,obj_coefs,reactions):
+   
+    # Set the coefficients of the objective function
+    i=1
+    for ind_coef in obj_coefs:
+        glp_set_obj_coef(lp, i, ind_coef);
+        i+=1
+
+    # Initialize the parameters    
+    params=glp_smcp()
+    params.presolve=GLP_ON
+    params.msg_lev = GLP_MSG_ALL
+    params.tm_lim=4000
+    glp_init_smcp(params)
+    
+    # Solve the problem
+    glp_scale_prob(lp,GLP_SF_AUTO)
+    
+    value=glp_simplex(lp, params) 
+
+    Z = glp_get_obj_val(lp);
+
+    if value == 0:
+        fluxes = []
+        for i in range(len(reactions)): fluxes.append(glp_get_col_prim(lp, i+1))
+        return fluxes,Z
+    else:
+        raise Exception("error in LP problem. Problem:",str(value)) 
+    
+
+# Create LP structure
+def create_lp_structure(model):
+    
+    reactions=[el.id for el in model.reactions]
+    coefs_obj=[reaction.objective_coefficient for reaction in model.reactions]
+    
+    # Lower and upper bounds
+    lb=[reaction.lower_bound for reaction in model.reactions]
+    ub=[reaction.upper_bound for reaction in model.reactions]
+    
+    # Create S matrix
+    S=cb.util.create_stoichiometric_matrix(model,array_type="dok")
+    
+    return S,lb,ub,coefs_obj,reactions
+
+# CBS sampling interface
+def randomObjectiveFunctionSampling(model, nsample, coefficients_df, df_sample):
+
+    S,lb,ub,coefs_obj,reactions = create_lp_structure(model)
+    len_vector, values, indexes, ia, ja, ar, nrow, ncol = initialize_lp_problem(S)
+    
+    for i in range(nsample):
+      
+        coefs_obj=coefficients_df.iloc[:,i].values
+            
+        if coefs_obj[-1]==1: #minimize
+            coefs_obj= coefs_obj[0:-1] * -1
+        else:
+            coefs_obj=coefs_obj[0:-1]
+
+        fluxes,Z = create_and_solve_lp_problem(lb,ub, nrow, ncol, len_vector, 
+                                                        ia, ja, ar, coefs_obj,reactions,return_lp=False)
+        df_sample.loc[i] = fluxes 
+    pass
+
+def randomObjectiveFunctionSampling_cobrapy(model, nsample, coefficients_df, df_sample):
+    
+    for i in range(nsample):
+
+        dict_coeff={}
+        if(coefficients_df.iloc[-1][i]==1):
+            type_problem = -1 #minimize
+        else:
+            type_problem = 1
+            
+        for rxn in [reaction.id for reaction in model.reactions]:
+            dict_coeff[model.reactions.get_by_id(rxn)] = coefficients_df.loc[rxn][i] * type_problem
+            
+        model.objective = dict_coeff
+        solution =  model.optimize().fluxes
+        for rxn, flux in solution.items():
+            df_sample.loc[i][rxn] = flux
+
+    pass
+
+# Create random coefficients for CBS
+def randomObjectiveFunction(model, n_samples, df_fva, seed=0):
+    
+
+        #reactions = model.reactions
+        reactions = [reaction.id for reaction in model.reactions]
+        cont=seed
+        list_ex=reactions.copy()
+        list_ex.append("type_of_problem")
+        coefficients_df = pd.DataFrame(index=list_ex,columns=[str(i) for i in range(n_samples)])
+
+        for i in range(0, n_samples):
+           
+            cont=cont+1
+            random.seed(cont)
+            
+            # Genera un numero casuale tra 0 e 1
+            threshold = random.random() #coefficiente tra 0 e 1
+            
+            for reaction in reactions:
+
+                cont=cont+1
+                random.seed(cont)
+                        
+                val=random.random()   
+                
+                if val>threshold:
+
+                    cont=cont+1
+                    random.seed(cont)                           
+                   
+                    c=2*random.random()-1 #coefficiente tra -1 e 1
+                    
+                    val_max=np.max([df_fva.loc[reaction,"minimum"],df_fva.loc[reaction,"maximum"]])
+                    
+                    if val_max!=0: #solo se la fva è diversa da zero
+                        coefficients_df.loc[reaction,str(i)] = c/val_max #divido per la fva
+                    else:
+                        coefficients_df.loc[reaction,str(i)] = 0
+
+                else:
+                    coefficients_df.loc[reaction,str(i)] = 0
+
+            cont=cont+1
+            random.seed(cont)
+                    
+            if random.random()<0.5:
+                coefficients_df.loc["type_of_problem",str(i)] = 0 #maximize
+            else:
+                coefficients_df.loc["type_of_problem",str(i)] = 1 #minimize
+                            
+        return coefficients_df
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