# learnNoInputs.py - Learning ignoring all input features
# AIFCA Python3 code Version 0.9.4 Documentation at http://aipython.org
# Download the zip file and read aipython.pdf for documentation

# Artificial Intelligence: Foundations of Computational Agents http://artint.info
# Copyright David L Poole and Alan K Mackworth 2017-2022.
# This work is licensed under a Creative Commons
# Attribution-NonCommercial-ShareAlike 4.0 International License.
# See: http://creativecommons.org/licenses/by-nc-sa/4.0/deed.en

from learnProblem import Evaluate
import math, random, collections, statistics
import utilities  # argmax for (element,value) pairs

class Predict(object):
    """The class of prediction methods for a list of values.
    Please make the doc strings the same length, because they are used in tables.
    Note that we don't need self argument, as we are creating Predict objects,
    To use call Predict.laplace(data) etc."""

    ### The following return a distribution over values (for classification)
    def empirical(data, domain=[0,1], icount=0):
        "empirical dist   "
        # returns a distribution over values
        counts = {v:icount for v in domain}
        for e in data:
            counts[e] += 1
        s = sum(counts.values())
        return {k:v/s for (k,v) in counts.items()}

    def bounded_empirical(data, domain=[0,1], bound=0.01):
        "bounded empirical"
        return {k:min(max(v,bound),1-bound) for (k,v) in Predict.empirical(data, domain).items()}

    def laplace(data, domain=[0,1]):
        "Laplace         "  # for categorical data
        return Predict.empirical(data, domain, icount=1)

    def cmode(data, domain=[0,1]):
        "mode            " # for categorical data
        md = statistics.mode(data)
        return {v: 1 if v==md else 0 for v in domain}

    def cmedian(data, domain=[0,1]):
        "median          " # for categorical data
        md = statistics.median_low(data)  # always return one of the values
        return {v: 1 if v==md else 0 for v in domain}
        
    ### The following return a single prediction (for regression). domain is ignored.
    
    def mean(data, domain=[0,1]):
        "mean            "
        # returns a real number
        return statistics.mean(data)

    def rmean(data, domain=[0,1], mean0=0, pseudo_count=1):
        "regularized mean"
        # returns a real number.
        # mean0 is the mean to be used for 0 data points
        # With mean0=0.5, pseudo_count=2, same as laplace for [0,1] data
        # this works for enumerations as well as lists
        sum = mean0 * pseudo_count
        count = pseudo_count
        for e in data:
            sum += e
            count += 1
        return sum/count

    def mode(data, domain=[0,1]):
        "mode            "
        return statistics.mode(data)

    def median(data, domain=[0,1]):  
        "median          "
        return statistics.median(data)

    all = [empirical, mean, rmean, bounded_empirical, laplace, cmode, mode, median,cmedian]

    # The following suggests appropriate predictions as a function of the target type
    select = {"boolean": [empirical, bounded_empirical, laplace, cmode, cmedian],
              "categorical": [empirical, bounded_empirical, laplace, cmode, cmedian],
              "numeric": [mean, rmean, mode, median]}
def test_no_inputs(error_measures = Evaluate.all_criteria, num_samples=10000, test_size=10 ):
    for train_size in [1,2,3,4,5,10,20,100,1000]:
        results = {predictor: {error_measure: 0 for error_measure in error_measures}
                        for predictor in Predict.all}
        for sample in range(num_samples):
             prob = random.random()
             training = [1 if random.random()<prob else 0 for i in range(train_size)]
             test = [1 if random.random()<prob else 0 for i in range(test_size)]
             for predictor in Predict.all:
                 prediction = predictor(training)
                 for error_measure in error_measures:
                     results[predictor][error_measure] += sum( error_measure(prediction,actual) for actual in test)/test_size
        print(f"For training size {train_size}:")
        print("   Predictor\t","\t".join(error_measure.__doc__ for
                                           error_measure in error_measures),sep="\t")
        for predictor in Predict.all:
            print(f"   {predictor.__doc__}",
                      "\t".join("{:.7f}".format(results[predictor][error_measure]/num_samples)
                                    for error_measure in error_measures),sep="\t")
        
if __name__ == "__main__":
    test_no_inputs()